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MC145572FN - ISDN U-Interface Transceiver 44-PLCC | NXP
The NXP (formerly Motorola/Freescale) MC145572FN is a single-chip ISDN U-interface transceiver housed in a 44-pin PLCC (Plastic Leaded Chip Carrier) package. It implements the 2B1Q four-level line code defined by ANSI T1.601 for full-duplex digital transmission on a 2-wire metallic loop, supporting basic-rate access on the U reference point between the network termination (NT1) and the line card (LT). The device integrates echo cancellation, adaptive equalization, and a 2B+D (144 kbps) data channel into one CMOS IC originally developed by Motorola Semiconductor. An ISDN U-interface transceiver is the analog front-end IC that bridges digital ISDN terminal equipment with the 2-wire subscriber line. Within the broader telecom IC hierarchy, this places the part under "transceiver" -> "interface IC" -> "telecom IC" -> "specialized/communications IC." U-interface transceivers perform line equalization, adaptive gain control, and 2B1Q pulse-amplitude modulation while handling the long-loop attenuation of standard copper pairs up to approximately 18 kft. Key features of the MC145572FN include integrated 2B1Q codec, on-chip echo canceller, programmable pulse shaping, selectable line build-out for short/long loops, and an 8-bit microprocessor interface for control and status monitoring. The 44-pin PLCC (J-lead) package provides a robust through-hole-style leaded footprint suitable for legacy telecom line-card designs and is rated for the standard 0 to +70C commercial or extended industrial temperature grades depending on the screening option. Architecturally, the MC145572 combines a transmit pulse generator, receive path with adaptive decision feedback equalizer (DFE), and a digital framer/deframer on a single low-power CMOS die. The device operates from a single +5V supply and draws roughly 200 to 350 mW depending on loop length, dramatically simplifying the line card BOM compared to discrete bipolar echo-canceller designs of the early 1990s. It was a flagship IC of the original Motorola ISDN chipset, paired with the MC145574 S/T-interface transceiver and the MC68302 communications controller. Typical applications include ISDN basic-rate U-interface line cards (LT side), NT1 customer-premises equipment, digital loop carrier systems, and early DSL precursor designs. Engineers selected the MC145572FN because it removed the need for a separate analog front-end and DSP for 2B1Q line coding, dramatically reducing board area and time-to-market for ISDN BRI products. When designing with this part, pay close attention to PCB layout for the analog front-end section: keep the transmit and receive paths physically separated, provide a solid analog ground plane under the PLCC, and use the recommended transformer (typically a 1:1.36 or 1:2 turns ratio Pulse PE-68023 or equivalent) for isolation. Note that the MC145572FN has been classified as obsolete or last-time-buy for many years - verify current stock carefully and qualify any substitute thoroughly.
MC145572FNR2 - ISDN U-Interface Transceiver, 44-PLCC | NXP
The NXP (formerly Freescale/Motorola) MC145572FNR2 is an ISDN U-interface transceiver IC housed in a 44-pin PLCC (16.59 x 16.59 mm) J-leaded surface-mount package. It integrates the analog front-end and digital echo-cancellation functions required for full-duplex 2B1Q transmission over a 2-wire ISDN U-interface loop, and is designed to operate as a companion to the MC145574 S/T-interface transceiver in customer-premises equipment (CPE) or network-terminal designs. The device supports 4-wire full-duplex data flow at the standard ISDN Basic Rate Access (BRA) line rate of 160 kbps over twisted-pair copper loops up to approximately 5-6 km. An ISDN U-interface transceiver is a specialized line-interface IC that bridges digital terminal equipment and the 2-wire metallic local loop of the public switched telephone network. In the broader taxonomy, the MC145572FNR2 belongs to the ISDN transceiver family, which sits within telecom interface ICs and ultimately within the broader category of specialized interface ICs. The U-interface (defined in ANSI T1.601) is the reference point between the network termination 1 (NT1) and the line termination (LT) inside the central office; this part targets the network-side or terminal-side adaptive echo-canceller functions that allow 2B1Q baseband signalling to coexist on a single copper pair with echo cancellation. Key features include on-chip 2B1Q line coding/decoding, adaptive echo cancellation, a digital interface that connects to the companion MC145574 S/T device, programmable transmit pulse shaping, and receiver equalization. The die operates from a single +5 V supply and is fabricated in a mature CMOS process that has been qualified for sustained telecommunications deployment. PLCC-44 packaging allows drop-in compatibility with legacy ISDN designs and supports both socketed and surface-mount assembly in production. Typical applications include ISDN BRI terminal adapters, ISDN NT1 network terminations, ISDN-compatible routers, integrated voice/data terminal equipment, and industrial telecom interfaces where 2-wire full-duplex ISDN connectivity is required. Because the U-interface is largely obsolete in regions that have migrated to xDSL, fibre, and 4G/5G wireless, the part is mainly used for legacy support, repair, and equipment that must retain ISDN connectivity. When designing with the MC145572FNR2, ensure the +5 V rail is well-decoupled and that the 2-wire line side meets ANSI T1.601 longitudinal-balance and pulse-mask requirements. Thermal dissipation in the 44-PLCC package is modest because the part does not drive heavy line currents directly, but PCB layout should still provide a low-impedance ground return under the analog section. This page synthesizes distributor pricing, cross-reference alternatives, and practical design notes that are not found in the original Motorola/Freescale datasheet alone, helping engineers sourcing the MC145572FNR2 for legacy support, repair, or new ISDN-CPE designs.
MC145572PB - ISDN U-Interface Transceiver, 44-LQFP | NXP
The NXP MC145572PB is an ISDN U-interface transceiver housed in a 44-pin LQFP (10x10 mm) package, originally designed by Motorola and later transferred through Freescale to NXP. It is a specialized interface IC operating at 5V with an industrial temperature range of -30C to +85C, supporting data rates of up to 160 kbps for 2B1Q ISDN basic-rate-access (BRA) U-interface applications. An ISDN U-interface transceiver is a type of specialized interface IC that handles the physical-layer signaling between customer-premises equipment (CPE) and the central-office line card over a 2-wire full-duplex digital subscriber loop. Within the broader hierarchy, it sits under interface ICs -> telecom interface ICs -> specialized ICs -> integrated circuits -> semiconductors. The U-interface is the last-mile digital link that operates using echo-cancellation and 2B1Q line coding to deliver two 64-kbps bearer channels plus a 16-kbps D channel over standard twisted-pair copper wiring. Key features include integrated echo cancellation, adaptive equalization, and a 2B1Q line encoder/decoder, all on a single CMOS die. The device requires a single 5V supply and exposes digital serial interfaces for connection to an external S/T-interface transceiver or layer-1 controller. Its 44-LQFP (10x10) package offers a 0.8 mm lead pitch suited to industrial surface-mount assembly, and the industrial temperature grade makes it usable in outdoor customer-premises line units. Typical applications include ISDN basic-rate-access (BRA) terminal adapters, NT1 (Network Termination 1) units for residential and small-business ISDN service, ISDN test equipment, and legacy 2-wire digital-subscriber-loop modems. The 160 kbps line rate supports the standard 144 kbps user payload (2B+D) plus framing overhead. When designing with this part, designers should follow the reference PCB layout in the manufacturer datasheet and provide proper 2-wire transformer isolation between the line side and the digital side. Bulk decoupling on the 5V rail and a low-jitter system clock are required to meet ISDN pulse-template specifications. This page synthesizes distributor pricing, lifecycle status, and pin/packaging facts not consolidated in a single place on the manufacturer's datasheet, including a current cross-reference view of drop-in alternatives that share the 44-LQFP footprint.
MC145572PBR2 - ISDN U-Interface Transceiver | NXP | 44-LQFP
The NXP (formerly Freescale / Motorola) MC145572PBR2 is a single-chip ISDN U-interface transceiver designed for 160 kbps full-duplex 2B1Q transmission over a single twisted-pair copper line. Housed in a 44-pin LQFP (10x10 mm) surface-mount package, this specialized IC integrates the analog front-end, echo canceller, digital signal processor, and HDLC controller required for both the network-termination (NT) and line-termination (LT) sides of an ISDN basic-rate interface, with the side selected at power-up by a single pin. In the broader product hierarchy, the MC145572PBR2 is a specialized telecommunications IC — a sub-category of interface ICs that bridges the physical layer of legacy ISDN and 2B1Q transport systems to higher-layer HDLC processors. It belongs to the MC145572 product family, itself part of Motorola Semiconductor's original MC145xxx CMOS logic lineage that established the part-number convention later continued by Freescale and now NXP. The device operates from a single 5 V supply and consumes considerably less power than the discrete ISDN modem designs it replaced, making it the de-facto standard for U-interface NT1 reference designs, terminal adapters, and ISDN test equipment through the late 1990s and early 2000s. Key features include integrated adaptive echo cancellation, a built-in scrambler/descrambler compliant with ANSI T1.601-1992, an on-chip HDLC controller supporting up to four 16-bit or two 32-bit identifiers, and a Microprocessor-compatible parallel host interface. The transceiver supports both NT and LT modes via a strap pin, includes a programmable digital attenuator, and provides 2B+D channelization with automatic activation/deactivation. Diagnostic loopback and pattern-generation modes aid installation and field troubleshooting by telco technicians. Typical applications include ISDN basic-rate NT1 modems, terminal adapters, digital-loop carrier remote terminals, ISDN test and measurement equipment, and legacy PBX line cards connecting to a U-interface drop. The wide-protocol support also makes the device useful for industrial telemetry bridges that still rely on ISDN for guaranteed low-latency backhaul. When designing with the MC145572PBR2, supply decoupling matters more than for generic logic ICs: place 0.1 uF ceramic capacitors as close as possible to each VDD/VSS pair on the package. Trace the differential transmit pair and receive pair with controlled 100-ohm differential impedance, keep them routed away from switching power and clock lines, and provide at least 6 mm of clearance between the transformer secondary and any digital signal plane to avoid injecting common-mode noise into the receiver's high-gain analog front-end.
MC1488D - Quad EIA-232D Driver | onsemi | RS-232 Interface
The onsemi MC1488D is a monolithic four-channel EIA-232D line driver with a 14-pin SOIC package. It provides four current-limited differential outputs intended to interface data terminal equipment with data communications equipment, with typical output current limited to ±10 mA and a minimum power-off source impedance of 300 ohms. An EIA-232D line driver is a type of RS-232 interface driver that converts logic-level signals into the voltage-domain signals used by RS-232 communications equipment. Within the broader hierarchy, it is a line driver and interface IC within communications and power-management signal conditioning. Its four channels allow one package to support several unidirectional data paths when the system already provides the required receiver and supply circuitry. Key features include four independent driver channels, typical current-limited output of ±10 mA, and a minimum power-off source impedance of 300 ohms. The current limiting helps control output current when a receiver or connected circuit imposes an abnormal load. The MC1488D also provides simple slew-rate control, an important characteristic for reducing unwanted transitions on slow RS-232 links. Technically, the device is designed around the EIA-232D interface requirements identified in the onsemi datasheet. Because MC1488D contains drivers rather than receivers, it cannot replace a complete RS-232 transceiver without external receiver circuitry. In a typical interface, logic signals enter the driver inputs and leave through four EIA-232D output channels. The receiver and any required level translation are separate functions. Typical uses include legacy RS-232 ports, data terminal equipment, data communications equipment, industrial control interfaces, and embedded systems that retain an EIA-232D connection. The MC1488D is also useful as the transmit-side element in a multi-channel interface where a companion receiver IC is already present. Designers should verify the supported supply voltage, input thresholds, output levels, timing, and absolute maximum ratings directly against the manufacturer datasheet before implementation. PCB layout should preserve short output paths, provide an appropriate ground reference, and avoid placing sensitive analog signals beside the driver outputs. This page combines verified manufacturer and distributor information, source-backed drop-in candidates, interface-selection guidance, and practical PCB considerations to provide engineering context beyond a basic MC1488D catalog listing.
MC1488DG - Quad EIA-232D Driver | onsemi | RS-232 Interface
onsemi MC1488DG is a monolithic quad line driver designed to interface data terminal equipment with data communications equipment using the EIA-232D standard. The device provides four driver channels, operates from a 5 V supply, and uses a 14-pin SOIC package. Its typical output current is ±10 mA per channel, with current limiting built into the outputs. The MC1488DG is intended for RS-232 transmitter functions rather than receiver functions, so it must be paired with a suitable quad receiver when full bidirectional communication is required. An EIA-232D line driver is a type of interface transceiver component that converts logic-level signals into RS-232 voltage levels for transmission between data terminal equipment and data communications equipment. In the broader hierarchy, MC1488DG belongs to the interface IC category, specifically the RS-232 driver family. Its quad-channel architecture reduces the component count in systems requiring several serial data outputs while preserving the signal and power connection conventions established for EIA-232D equipment. The principal features of MC1488DG include four independent driver outputs, integrated output current limiting, and a typical output current capability of ±10 mA. The driver is designed for conformance with EIA-232D interface requirements, and its monolithic construction places the driver functions in one 14-pin SOIC package. The design supports equipment requiring multiple RS-232 transmit channels, including computer peripherals, industrial data links, test equipment, and legacy communications equipment. Technically, the MC1488 belongs to the family of bipolar RS-232 line drivers that use positive and negative supply rails to develop the bipolar voltage levels required by the interface standard. The MC1488 data also identifies SN55188 and SN75188 as related monolithic quadruple line drivers. Because MC1488DG is a driver-only device, engineers should check signal levels, supply requirements, output polarity, and protection needs against the original system interface before using it in a redesigned board. Typical applications include industrial serial-port controllers, laboratory instrumentation, point-of-sale terminals, data acquisition equipment, and embedded systems that retain an RS-232 output interface. In a multi-channel design, each logic input can drive a corresponding RS-232 output, while a separate receiver IC handles incoming signals. This separation is important because the MC1488 provides four transmit channels but no integrated receive channels. A key design consideration is to preserve the original board footprint and verify every pin assignment before substitution. The 14-pin SOIC package is suitable for conventional surface-mount assembly, but RS-232 cables connect to externally exposed connector pins rather than directly to the IC. External protection, grounding, connector geometry, and cable-routing decisions remain necessary to achieve reliable system-level communications. This page combines the verified manufacturer and distributor references for MC1488DG with package information, interface intent, sourcing links, and identified pin-compatible alternatives. It also distinguishes the driver-only MC1488DG from complete RS-232 transceiver functions, helping engineers select the correct replacement without confusing interface direction or package compatibility.
MC1488M - Quad EIA-232D Driver, SOIC-14 | onsemi
onsemi MC1488M is a monolithic quad line EIA-232D driver with four current-limited outputs, supplied in a 14-pin SOIC package. The device provides typical output currents of ±10 mA and a minimum power-off source impedance of 300 Ω. It is designed to interface data terminal equipment with data communications equipment using the EIA-232D signal convention. An EIA-232D line driver is a transmitter within the broader interface IC and RS-232 transceiver categories. Its role is to convert logic-level transmit signals into bipolar voltage levels suitable for EIA-232D communication links. The MC1488M contains four independent driver channels, allowing one package to support multiple serial-data outputs in equipment such as modems, computer interfaces, industrial communications equipment, and legacy peripheral systems. The principal features of the MC1488M include four driver channels, typical current-limited output capability of ±10 mA, a 300 Ω minimum power-off source impedance, and EIA-232D interface conformance. Its 14-pin SOIC package supports surface-mount PCB assembly while reducing the footprint required by a discrete transistor driver arrangement. The M suffix identifies the surface-mount ordering variant presented by onsemi. Internally, the MC1488M combines four line-driver stages with supply-voltage protection arrangements described in the associated device literature. Its monolithic construction provides a practical alternative to separate transistor or MOSFET driver circuits. Because the output stage is designed to source and sink current rather than operate as a logic-level CMOS output, the circuit should be evaluated as an EIA-232D interface stage, not as a general-purpose push-pull logic driver. Typical uses include four-channel RS-232 transmit ports, data terminal equipment, data communications equipment, printer interfaces, and industrial data links. Designers combining this driver with a receiver can construct a complete asymmetric RS-232 interface. The component is especially relevant to legacy systems that require more than two independently driven EIA-232D outputs while retaining a surface-mount footprint. The primary design consideration is the external interface network and supply arrangement. EIA-232D implementations commonly use series resistors and capacitive or diode-clamped protection to manage transient conditions, while supply bypassing must be placed close to the device. Engineers should also verify receiver compatibility, cable requirements, logic levels, and all electrical limits against the manufacturer datasheet before substituting the part into a live design. This product page consolidates the verified manufacturer and distributor information for MC1488M with package details, sourcing guidance, practical design notes, and a strict assessment of available drop-in alternatives. Where the supplied source material does not establish an exact same-package replacement, the page identifies that limitation instead of presenting an unverified substitution as drop-in compatible.
MC1488MG - Quad EIA-232D Driver | onsemi | RS-232
The onsemi MC1488MG is a monolithic four-channel RS-232 line driver with a 4/0 driver-to-receiver configuration, current-limited outputs rated at ±10 mA typical, and a 14-pin gull-wing SOIC package. It is designed for data-terminal equipment and data-communications equipment that require an EIA-232D-compatible transmit interface. The MC1488MG is identified as the commercial extended-temperature grade in distributor and catalog records. An RS-232 line driver is an interface IC that converts digital logic-level signals into unbalanced, bipolar voltage levels suitable for serial data links. Within the signal-chain hierarchy, it belongs to the RS-232 interface-driver family, combines with an RS-232 receiver to form a complete communications path, and ultimately provides the physical-layer function required between data terminal equipment and data communications equipment. Unlike a transceiver, the MC1488MG provides four driver channels and no receiver channels. The primary verified characteristics are four independently available line-driver outputs, EIA-232D conformance, typical current limiting of ±10 mA, a 14-pin SOIC package with gull-wing leads, and a commercial extended temperature grade. The output current limit protects the driver stage when a connected RS-232 line is shorted or misconfigured. Because four transmit channels are provided, one device can support four RS-232 outputs while reducing the number of external line-driver packages required. The MC1488MG is intended for legacy and industrial serial-control equipment where EIA-232D signaling remains required. Appropriate uses include multi-port controller interfaces, equipment test systems, point-to-point serial links, and control panels. The device requires suitable bypass capacitance and careful grounding because the implemented system also depends on cable characteristics, receiver thresholds, protection networks, and the voltage levels allowed by the selected RS-232 endpoint. For new designs, engineers should verify signal polarity, baud rate, logic thresholds, and electrical limits against the current manufacturer datasheet before layout release. The supplied search results confirm the EIA-232D driver function, four-output organization, ±10 mA typical output current, and 14-pin SOIC format, but several detailed timing, voltage, temperature, and absolute-maximum values were not included in the retrieved records. This page combines verified distributor and manufacturer-linked information, structured technical context, pin-compatible replacement guidance, and practical sourcing notes. It also separates confirmed electrical facts from parameters that require datasheet verification, helping engineers avoid assigning unsupported specifications to this legacy-compatible RS-232 interface device.
MC1488N - Quadruple RS-232 Line Driver | Texas Instruments
Texas Instruments MC1488N is a monolithic quadruple RS-232 line driver with four driver channels, 10 mA typical current-limited output, and a minimum 300 ohm power-off output impedance. Designed for data-terminal equipment and data-communications equipment interfaces, the device operates from a 5 V supply in a 14-pin PDIP package rated for 0 to 70 degrees C. A line driver is a digital interface circuit that converts low-voltage logic signals into RS-232-compatible voltage levels. The MC1488 belongs to the RS-232 driver hierarchy, where a line driver interfaces data-terminal equipment with data-communications equipment. Its four channels allow one package to support four unidirectional serial data paths, reducing component count in multi-port or multi-channel RS-232 equipment. The device is designed to meet or exceed ANSI EIA/TIA-232-E and ITU Recommendation V.28 requirements. According to the Texas Instruments manufacturer datasheet, each output includes current limiting, and the power-off output impedance is at least 300 ohms. A series diode is used at each supply-voltage terminal, while the output slew rate can be controlled through the load capacitance connected to each driver. The MC1488N is designed to be interchangeable with the Motorola MC1488, which supports PCB sourcing flexibility where the original function is required. The manufacturer datasheet identifies the MC1488, SN55188, and SN75188 as monolithic quadruple line drivers, but device ordering suffixes, temperature ranges, and package variants must still be checked before substitution. The N suffix identifies the 14-pin PDIP configuration shown in the verified Texas Instruments part-details data. Typical uses include RS-232 interfaces in data-terminal equipment, data-communications equipment, industrial control systems, point-of-sale equipment, printers, and legacy serial-port adapters. It is particularly useful where multiple RS-232 channels share a common logic interface and a through-hole package is preferred for serviceability or manual assembly. PCB layout should keep each driver output away from sensitive analog and high-speed digital traces because RS-232 transitions can produce edge-related EMI. The data input pins must be driven only when the supply is valid, and unused outputs should be handled according to the manufacturer datasheet rather than left as floating high-impedance nodes. Confirm output polarity and logic levels before interchanging it with a receive/transceiver device.
MC1488P - Quad RS-232 Line Driver | STMicroelectronics
The STMicroelectronics MC1488P is a monolithic quadruple RS-232 line driver with four differential driver channels in a 14-pin PDIP package. According to the verified manufacturer and distributor information, the device is intended to interface data terminal equipment with data communications equipment under EIA RS-232C and EIA-232D requirements. Its outputs are current limited to ±10 mA typical, while the power-off source impedance is specified at 300 ohms minimum. These characteristics make the MC1488P suitable for legacy RS-232 equipment requiring four unidirectional data channels, especially systems built around the classic MC1488 interface family. A line driver is a digital interface component that converts TTL-compatible logic signals into voltage levels suitable for a balanced or unbalanced communications link. In the broader electronics hierarchy, the MC1488P belongs to interface ICs, specifically the RS-232 driver category. It complements receiver ICs such as the MC1489 rather than operating as a complete bidirectional transceiver. Each of its four channels therefore supports one driven signal path per package. The principal verified features are the monolithic four-channel implementation, RS-232 interface purpose, ±10 mA typical current-limited outputs, 300 ohms minimum power-off source impedance, and 14-pin PDIP construction. The DigiKey listing identifies the device as a 4/0 RS-232 driver in a 14-DIP package, while Mouser categorizes it as a quad line driver. These are legacy communications characteristics rather than modern high-speed differential-interface specifications. The MC1488P is normally powered from separate positive and negative supply rails so that its output stage can generate RS-232 voltage levels from low-voltage logic. Exact supply limits, propagation delay, output-voltage levels, operating temperature, and absolute maximum ratings are not included in the supplied search records, so those values must be verified against the original manufacturer datasheet before a new design is released. The MC1488P may also need external charge-pump circuitry when used with modern single-supply systems because it does not include an on-chip RS-232 voltage converter. Typical uses include legacy serial-port adapters, industrial data-collection equipment, point-of-sale terminals, laboratory interfaces, and controller boards that exchange RS-232 signals with older peripherals. In each case, the MC1488P handles the transmit side, while a compatible receiver handles incoming signals. Software handshaking, ground continuity, and protection against external cable transients remain important system-level considerations. Designers should preserve the original 14-pin footprint and verify pin functions, supply rails, and logic thresholds against the applicable datasheet. Decoupling capacitors should be placed close to the supply pins, and cable-side protection may be required for industrial environments. Because the verified sources identify both STMicroelectronics and onsemi offerings, purchasing decisions should also account for manufacturer traceability, lifecycle status, and approved-source documentation. This page consolidates the verified RS-232 line-driver description, distributor identification, package information, drop-in substitution evidence, and practical design considerations into one engineering-focused reference. It also distinguishes verified facts from specifications that still require confirmation from the complete manufacturer datasheet.
MC1488PG - Quad RS-232 Line Driver | onsemi | PDIP-14
The onsemi MC1488PG is a monolithic quadruple RS-232 line driver with four driver outputs, designed for EIA-232D data-terminal and data-communications equipment interfaces. The device operates from a single positive supply, provides current-limited outputs with a typical ±10 mA output capability, and is packaged in a 14-pin PDIP format. Its four independent channels allow one interface IC to drive four RS-232 data signals while reducing the number of packages required on a communications board. An RS-232 line driver is a digital interface component that converts TTL-compatible logic levels into bipolar voltage levels suitable for transmission over an RS-232 port. A line driver belongs to the broader interface IC hierarchy and works alongside line receivers, transceivers, and protection devices in the wider data-communications and industrial-control equipment category. The MC1488 therefore provides the transmit-side function in a conventional RS-232 interface, while a separate receiver is required for incoming signals. Key features include four driver channels in one monolithic package and current-limited outputs rated to ±10 mA typical. The MC1488PG is associated with EIA-232D interface requirements and uses a 14-pin PDIP package for through-hole PCB assembly. These characteristics make it suitable for legacy computer ports, industrial control links, embedded serial equipment, and other systems that continue to use the bipolar RS-232 physical interface. The four driver outputs allow several communications lines to share the same supply and package, reducing PCB component count compared with discrete single-channel driver designs. Because the outputs are current limited, the device is suited to driving conventional RS-232 loads rather than high-current or long-distance cable networks. Designers should still provide the required bypass capacitance, observe the supply-voltage limits, and verify receiver and cable characteristics at the system level. Typical applications include multi-channel RS-232 equipment interfaces, legacy PC communication ports, test instruments, point-to-point industrial serial links, and embedded control systems. The four-channel arrangement is particularly useful when a board must transmit several RS-232 signals through a single interface package. A complementary receiver, such as a compatible RS-232 receiver IC, is required when the same port must also receive data. For a new PCB, confirm the manufacturer's MC1488 datasheet for the exact pin assignment, supply limits, output-current conditions, and decoupling recommendations. For an existing board, verify footprint, pinout, logic polarity, and operating-voltage compatibility before substitution, especially when the assembly includes protection networks or unusual cable loading. This product page combines the MC1488PG device identity, RS-232 design considerations, drop-in replacement guidance, and practical application context to help engineers evaluate legacy-interface repair, modernization, and sourcing decisions without relying on a raw catalog listing.
MC1489AM - Quad EIA-232D Receiver | onsemi | SOIC-14
onsemi MC1489AM is a monolithic quad line receiver designed to interface data terminal equipment with data communications equipment conforming to EIA-232D. The device combines four receiver channels in a 14-pin SOIC package, with an input resistance specified from 3.0 kΩ to 7.0 kΩ and an input signal range extending to 30 V. It is intended for systems that receive bipolar RS-232 signals and translate them into logic-level signals for the receiving equipment. The MC1489AM is a receiver-only device rather than a combined RS-232 transceiver. An EIA-232D line receiver belongs to the interface IC hierarchy, where it sits between a physical communication port and digital logic. RS-232 uses single-ended bipolar signaling, so a receiver must identify valid positive and negative voltages while rejecting signals outside the accepted logic thresholds. The four independent channels of the MC1489AM allow one package to handle four serial ports, four peripheral connections, or several control signals carrying the same receiver electrical characteristics. The primary electrical feature is its 3.0 kΩ to 7.0 kΩ input resistance. This relatively high impedance limits loading on the transmitting side and is useful when several receiver inputs must observe a signal source. The 30 V input signal range provides tolerance for voltage excursions on the physical line. Because the package contains four channels, it also reduces component count and board space compared with four separate single-channel receiver packages. The MC1489AM is specifically identified as an EIA-232D receiver rather than a modern transceiver with integrated charge-pump voltage generation. In a complete RS-232 interface, the MC1489AM is used on the receive path, while a separate line driver handles the transmit path. This separation can be advantageous in asymmetric equipment, test systems, industrial controllers, and legacy installations where the number of transmitted and received signals differs substantially. Common applications include industrial serial-port interfaces, data terminal equipment, data communications equipment, peripheral controllers, instrumentation, and legacy computer equipment. Designers should provide the interface system with an appropriate common reference and route the receive outputs directly into the receiving logic or level-shifting circuitry required by the host device. When laying out a circuit using the MC1489AM, keep the receiver close to the connector or protected signal entry point to minimize the distance over which unprotected RS-232 signals can pick up noise. The input network should avoid excessive loading because the receiver input resistance can vary across the stated 3.0 kΩ to 7.0 kΩ range. Confirm the complete pin assignment, voltage limits, and system enable requirements against the manufacturer datasheet before fabrication. This product page combines the verified device identity, package information, and electrical characteristics with application guidance, design considerations, and a conservative drop-in replacement assessment. It is structured to help engineers identify the correct receiver function, plan the interface architecture, and avoid treating functionally similar receivers as pin-compatible replacements.
MC1489AN - Quad RS-232 Receiver, 5V, 14-PDIP | Texas Instruments
The Texas Instruments MC1489AN is a quadruple RS-232 line receiver integrated circuit with four independent receiver channels, a 4.5 V to 5.5 V single supply, and a 14-pin PDIP package. Its stated input resistance is 7 kΩ, while the receiver supports input signal voltages up to 30 V. Each channel includes double-threshold input hysteresis and an external response-control connection that provides input-threshold shifting and noise filtering. A line receiver is an interface IC that converts bipolar RS-232 signals into logic-level digital signals. In the signal hierarchy, an RS-232 line receiver belongs to the broader category of interface ICs, communication transceivers, and data-conversion devices. The MC1489AN is intended specifically for the receiver side of a data-terminal-equipment to data-communication-equipment interface, where one connector may carry several low-speed serial signals and the cable may introduce threshold noise or unwanted voltage excursions. The principal feature of the MC1489AN is its four-channel integration in one 14-pin PDIP. Each receiver can be associated with a response-control terminal, allowing the design to tune threshold behavior and rejection of input noise. The built-in hysteresis gives the digital output a defined switching interval, reducing uncertainty when a slow or noisy input crosses the detection threshold. The receiver architecture is based on low-power Schottky technology and operates from one 5 V supply. According to the manufacturer datasheet, the MC1489AN is designed to meet or exceed the requirements of the TIA/EIA-232-F interface standard. Its 7 kΩ input resistance helps limit loading on the transmitting side, and its specified input-signal range extends to 30 V. These characteristics make it suitable for legacy RS-232 equipment, multi-port data acquisition interfaces, industrial control links, and equipment that must retain compatibility with established D-sub serial interfaces. The MC1489AN is most useful when a board needs more than one receive channel without allocating a separate single-channel receiver package to every port. Typical uses include four-wire industrial serial links, legacy printer interfaces, service-console connections, and test equipment. Because it is a receiver rather than a complete transceiver, the design must provide a separate line driver for each direction that requires transmission. Designers should review the complete pinout and recommended circuit before layout because the response-control terminals and input protection structure influence signal behavior. Place the receiver close to the connector or protected interface boundary, maintain the specified bypass capacitance, and route high-voltage or externally accessible receive lines away from sensitive logic. The verified public search results also identify a comparison with DS14C89AN/NOPB, which uses lower-power CMOS technology, but the complete device-specific values are not present in the supplied data. This page combines verified manufacturer and distributor information with package-level alternatives, application guidance, and design considerations. It distinguishes directly cited characteristics from unavailable specifications, helping engineers evaluate the MC1489AN without treating search-result summaries as complete datasheet data.
MC1489AP - Quad RS-232 Receiver | STMicroelectronics
STMicroelectronics MC1489AP is a monolithic quad line receiver designed for RS-232 data-terminal and data-communication interfaces, with four receiver channels in a 14-pin DIP package. The device provides a 3.0 kΩ to 7.0 kΩ input resistance, low-power Schottky construction, and a separate response-control terminal for each receiver. It is associated with the TIA/EIA-232-F interface standard and is also described as supporting RS-232C and EIA-232-D requirements. An RS-232 receiver is a line-interface component that converts bipolar serial data arriving at a communications port into logic-level signals for a digital system. The MC1489AP belongs to the line-receiver hierarchy within interface ICs and combines four channels in one package. Its response-control terminals allow each input stage to be configured with external resistors or a resistor and bias-voltage source, giving the designer control over operating thresholds and system behavior. The quad-channel architecture reduces component count on equipment requiring multiple serial ports or several control links. Its specified input resistance of 3.0 kΩ to 7.0 kΩ is important when designing cable termination, biasing, and logic-threshold networks. The separate response-control terminals are the principal functional feature distinguishing this receiver family from simpler integrated transceivers that package fixed driver and receiver functions together. The MC1489AP is based on low-power Schottky line-receiver circuitry. According to the available manufacturer descriptions, the monolithic design was intended to satisfy the interface requirements between data-terminal equipment and data-communication equipment under EIA and TIA/EIA RS-232 definitions. Because each channel includes its own response-control connection, the external network must be selected with the system voltage, signal polarity, and desired threshold in mind rather than treated as a fixed internal configuration. Typical uses include industrial data acquisition, legacy peripheral interfaces, serial-control equipment, instrumentation, and embedded systems that retain RS-232 ports. The device is also useful when four independent receive channels can share a common logic supply and ground arrangement. Its DIP-14 format is appropriate for through-hole legacy designs, although modern compact products generally favor surface-mount interface ICs. For reliable implementation, verify the receiver supply voltage, input voltage limits, logic thresholds, and response-control network against the complete MC1489AP datasheet before layout release. Decoupling and grounding remain important because an RS-232 receiver may be positioned near a noisy cable entry point even though it is not the transmitter. Keep input and control networks away from switching nodes and use a stable, low-impedance ground reference to minimize threshold shifts. This product page combines verified manufacturer and distributor facts with same-package alternatives, parameter-level comparison data, and practical implementation guidance. It also distinguishes confirmed MC1489AP characteristics from parameters that require confirmation from the complete datasheet, helping engineers evaluate this legacy RS-232 interface device without relying on unsupported assumptions.
MC1489D - Quad EIA-232D Line Receiver | onsemi | SOIC-14
The onsemi MC1489D is a monolithic quad EIA-232D line receiver that converts four differential or bipolar serial data inputs into four compatible logic-level receiver outputs. Its 14-pin SOIC package, 3.0 kΩ to 7.0 kΩ input resistance, and approximately ±30 V input signal range support legacy RS-232 equipment interfaces. The MC1489D is designed for data terminal equipment and data communications equipment operating in conformance with EIA Standard EIA-232D. A line receiver, also called an RS-232 receiver, is an interface IC that recovers digital data from a ±3 V to ±15 V RS-232 signal while rejecting the common-mode voltage present on long cables. Within the interface hierarchy, the MC1489D belongs to the receiver subset of RS-232 line drivers and receivers, which sits inside the broader class of interface ICs and communication transceivers. A receive-only device is useful when the system already provides a separate transmitter, such as the MC1458D or MAX232DR. The headline characteristics of the MC1489D are its four-channel receiver architecture, 3.0 kΩ to 7.0 kΩ input resistance, and approximately ±30 V input signal capability. Each receiver provides threshold control that can accommodate both positive- and negative-going RS-232 signals. The monolithic construction reduces the external component count compared with discrete transistor receiver networks, while the 14-lead SOIC package simplifies assembly in legacy communications equipment. Operationally, the MC1489D accepts bipolar line signals and produces a logic-level indication of the signal state. The receiver input resistance limits current drawn from the RS-232 driver and influences the termination and biasing network selected by the system designer. Because the MC1489D implements EIA-232D rather than the later EIA-232-F revision, designers should verify that its electrical limits match the exact cable, driver, and system requirements rather than assuming interchangeability with every modern RS-232 controller. Typical uses include legacy terminal adapters, printer and workstation interfaces, industrial data acquisition, test equipment, and communication links that retain an MC1489-family receiver. It is particularly appropriate where four receive channels are needed in a single package and where the incoming signal can exceed the logic-level swing accepted by a CMOS or TTL input. The primary design consideration is to verify the receiver threshold network, exposed supply limitations, and available pin data against the exact manufacturer datasheet revision before layout. Because the provided source data does not enumerate a complete MC1489D pin table or maximum supply rating, those values should be confirmed before a new PCB is released. This page combines the verified onsemi and distributor sources with engineering guidance on RS-232 receiver selection, interface thresholds, legacy compatibility, and available drop-in alternatives. It also separates documented specifications from unverified parameters so procurement and design decisions are based on traceable evidence.
MC1489DG - Quad EIA-232D Line Receiver | onsemi
onsemi MC1489DG is a monolithic quad line receiver designed for EIA-232D data-terminal and data-communications interfaces. The device contains four receiver channels, accepts input signals ranging to plus or minus 30 V, and provides an input resistance of 3.0 kOhm to 7.0 kOhm. It is packaged in a 14-pin SOIC measuring approximately 3.90 mm wide with 0.154 inch lead pitch. An EIA-232D line receiver is an interface circuit that converts bipolar RS-232 signals into digital logic levels. It belongs to the receiver category within the broader RS-232 interface IC family. Because RS-232 uses voltage levels and signal conventions that differ from TTL and CMOS logic, a receiver is required between a physical communications port and the digital electronics that process the data. The MC1489DG's four independent receiver sections allow one package to serve several communications channels or several distinct RS-232 ports. Its plus or minus 30 V input signal range provides margin for the voltage excursions encountered in EIA-232D systems. The 3.0 kOhm to 7.0 kOhm input-resistance range identifies the device as a bipolar line receiver rather than a low-voltage CMOS transceiver. The 14-pin SOIC is a surface-mount package suitable for conventional PCB assembly and automated production. Its 0.154 inch pitch matches the widely used narrow-body SOIC footprint family, while the 3.90 mm body width supports compact placement compared with older through-hole receiver packages. Each receiver channel requires the correct external connection and signal conditioning defined by the system interface. Typical uses include RS-232 links between industrial equipment and computers, legacy peripheral ports, point-of-sale equipment, data acquisition systems, and embedded-control consoles. The quad organization is especially useful where four RS-232 inputs must be accepted without installing four separate receiver packages. Designers should still verify channel direction, grounding, signal polarity, and timing against the circuit being interfaced. A key design consideration is that MC1489DG is a receive-only interface. It does not provide the transmit functions required for a complete bidirectional RS-232 port. A separate line driver or transceiver is needed for outbound data. Board design must also preserve adequate spacing and signal return paths so large RS-232 voltage transitions do not create unwanted coupling into nearby low-level circuits. This product page combines manufacturer interface information, package details, application guidance, and focused replacement comparisons for engineers evaluating the MC1489DG in legacy and industrial RS-232 equipment.
MC1489M - Quad EIA-232D Receiver | onsemi | SOIC-14
The onsemi MC1489M is a monolithic quad EIA-232D line receiver with four independent receive channels, a 3.0 kΩ to 7.0 kΩ input resistance, and an input signal range of ±30 V. The device is supplied in a 14-pin SOIC (SOEIAJ-14) surface-mount package for compact data-terminal and data-communications equipment designs. Its receive-oriented architecture converts bipolar RS-232 signals into digital logic levels while providing response-control terminals for adjustable receiver behavior. A line receiver is an interface IC used at the receiving end of a serial communications link. The MC1489M belongs to the broader line-receiver hierarchy, which includes EIA-232D receivers, interface transceivers, and multi-channel communications interface ICs. Its four channels allow one package to support four RS-232 data inputs, reducing component count in equipment with several serial ports, control links, or diagnostic interfaces. The principal verified features include four receiver channels, 3.0 kΩ to 7.0 kΩ input resistance, and ±30 V input signal capability. Each receiver includes a response-control terminal to which a resistor, or a resistor and bias-voltage source, can be connected. This control allows the receiving behavior to be adjusted when the interface must accommodate different signaling thresholds or system-level conditions. The MC1489M uses Schottky-related input structures to support low-power operation while receiving high-voltage bipolar signals. This is useful in EIA-232D equipment because the transmitter side supplies positive and negative voltages relative to the logic ground. The receiver therefore must tolerate a substantially wider input range than the logic devices connected to its outputs. The four-channel arrangement also preserves separate receive paths for simultaneous or independently controlled links. Typical uses include RS-232 data-terminal equipment, industrial serial interfaces, instrumentation links, peripheral ports, and embedded systems that receive bipolar serial data. In such equipment, the MC1489M can sit between an external RS-232 connector and TTL or CMOS logic. The logic source impedance, grounding arrangement, and response-control network must be selected so the complete interface meets the intended EIA-232D system requirements. Designers should pay particular attention to supply grounding, receiver input protection, unused control pins, and signal routing. A solid signal-ground reference, controlled traces, and appropriate input resistors are essential because RS-232 connectors can be exposed to ESD and other transients. Pin functions and electrical limits must be confirmed against the manufacturer datasheet before layout release or substitution. This product record combines the verified onsemi datasheet information, distributor availability references, cross-reference candidates, and engineering-oriented selection guidance. It distinguishes confirmed drop-in candidates from general functional equivalents and highlights where additional electrical or lifecycle verification is still required.
MC1489MG - Quad EIA-232D Receiver | onsemi | 14-SOIC
The onsemi MC1489MG is a monolithic quadruple EIA-232D line receiver designed for data-terminal equipment and data-communication equipment interfaces. It contains four receiver channels in a 14-pin SOIC package, accepts input signals ranging from ±30 V, and presents an input resistance between 3.0 kΩ and 7.0 kΩ. The MC1489MG is identified as a commercial extended-temperature grade device. An EIA-232 line receiver is an interface IC that converts bipolar RS-232 voltage levels into digital logic levels. It belongs to the line-receiver class within interface ICs, a larger functional group that also includes RS-232 drivers, transceivers, and multi-protocol interface devices. Unlike a transceiver, the MC1489MG performs reception only, allowing equipment with separate transmit and receive signal paths to use a dedicated receiver for each direction. The four-channel architecture reduces the component count in equipment that exchanges multiple serial signals. Each receiver has a response-control function, which permits a resistor or a resistor and bias-voltage source to influence receiver behavior. Input resistance of 3.0 kΩ to 7.0 kΩ provides the required input loading for EIA-232D interfaces, while the ±30 V input signal range supports the voltage excursions characteristic of RS-232 signaling. The MC1489MG is based on a monolithic low-power Schottky receiver design. This implementation supports four independent receive channels without requiring a separate receiver package for every signal. Because the part contains receivers rather than transmitters, it cannot independently generate the RS-232 voltage swings required to drive a remote communication port; it must be paired with an appropriate line driver when a design needs both transmission and reception. Typical uses include industrial serial interfaces, data-terminal equipment, data-communication equipment, remote-control links, and legacy RS-232 ports. The device is particularly relevant when an existing design requires four receive channels in a single 14-pin surface-mount package. Its commercial extended temperature designation also makes it a candidate for equipment operating outside the usual consumer temperature range. PCB design should preserve the EIA-232 input network, provide a stable supply and ground reference, and route each receiver input away from fast switching or high-current paths. The response-control terminals should be left at the configuration shown in the manufacturer application guidance. Review the pin-description table and operating limits in the manufacturer datasheet before finalizing the footprint and external networks.
MC1489N - Quad RS-232 Line Receiver | Texas Instruments
The Texas Instruments MC1489N is a monolithic quadruple RS-232 line receiver designed for TIA/EIA-232-F data-terminal and data-communication interfaces. It provides four receiver channels, operates from a single 4.5 V to 5.5 V supply, accepts input signals spanning ±30 V, and is offered in a 14-pin PDIP package. Each receiver includes a response-control input that supports threshold shifting and input-noise filtering. A line receiver is an interface-circuit category used to convert bipolar RS-232 signals into logic-level signals suitable for digital equipment. In the broader hierarchy, a receiver belongs to an interface IC, then to a communications or transceiver IC, and ultimately to the semiconductor family. The MC1489N is a receive-only counterpart to RS-232 driver ICs and is suitable wherever a design needs multiple incoming serial-data channels but no integrated transmit channels. The principal features include four independent receivers, a low-power Schottky implementation, approximately 7 kΩ input resistance, a ±30 V input signal range, and operation from one 4.5 V to 5.5 V supply. Built-in input hysteresis provides double switching thresholds, which helps prevent noise from repeatedly changing receiver output states around a transition point. The response-control terminals provide additional control over receiver thresholds and noise filtering. Technically, the MC1489N separates the high-voltage RS-232 input domain from the digital output domain. Each channel accepts a bipolar signal referenced to the receiver's ground, while the receiver's response-control terminal can be connected to a resistor or to a resistor and bias-voltage source. This arrangement permits circuit-level adjustment when a system requires particular threshold or filtering behavior. Typical applications include multi-channel serial data acquisition, industrial control links, legacy peripheral interfaces, test equipment, point-to-point communications equipment, and systems requiring several RS-232 inputs. The 14-pin PDIP package also makes the device suitable for through-hole prototypes and designs assembled with conventional DIP sockets. When laying out a board around the MC1489N, keep each input route away from fast digital switching nodes and connect its response-control network close to the relevant receiver pin. Because the device is receive-only, a separate RS-232 driver is required for a design that also needs to transmit. The supplied manufacturer and distributor sources do not publish a complete verified pin table or current unit price in the retrieved data. This page consolidates the verified manufacturer description, package and supply information, distributor availability references, and carefully qualified replacement candidates. It also adds comparison, application, and design guidance that is not normally visible in a short distributor listing, while clearly separating verified facts from values that still require datasheet or distributor confirmation.
MC1489P - Quad RS-232 Line Receiver | STMicroelectronics
The STMicroelectronics MC1489P is a four-channel RS-232 line receiver IC with a 14-pin PDIP package. The device accepts four receiver channels, provides logic threshold shifting, incorporates input hysteresis, and includes built-in response control for input-noise filtering. According to the manufacturer datasheet listing, the input resistance is 7 kΩ, the input signal range is ±30 V, and the maximum supply voltage is 10 V. A line receiver is an interface IC that converts electrical signals arriving over a communication link into logic-level signals for a host controller. As part of the broader hierarchy of interface ICs, line receivers belong to the RS-232 transceiver family and operate alongside line drivers in point-to-point or multidrop serial interfaces. The MC1489P provides four receivers in one package, allowing one device to handle four incoming data channels while reducing board area and component count. The receiver architecture includes logic threshold shifting, which accommodates RS-232 negative and positive signaling, and input hysteresis, which helps the receiver maintain a defined switching state in the presence of small input-voltage variations. The built-in response control provides input-noise filtering, making the MC1489P suitable for systems where the received serial data must be converted into dependable digital levels. A maximum supply voltage of 10 V provides the key verified operating limit for the supplied device. The MC1489P is identified as a commercial extended part in the available product data, with an operating temperature range of 0°C to +70°C and a PDIP-14 through-hole package. It is supplied in a tube format for automated or manual production handling. The four-channel arrangement is useful in industrial control links, peripheral interfaces, instrumentation, and embedded systems that need several receive functions without using four separate single-channel receiver packages. Typical applications include multi-channel RS-232 equipment interfaces, industrial controller serial ports, data-acquisition equipment, test and measurement systems, and embedded control consoles. Because the verified data identifies the part as a receiver rather than a combined transceiver, it is best used on the receive side of an RS-232 connection. A transmit driver may be required separately when the same board also needs to originate RS-232 signals. The primary design consideration is to validate every external signal against the documented ±30 V input range and to operate the receiver from a supply no greater than 10 V. PCB layout should preserve the pin assignments of the PDIP-14 footprint, provide an unobstructed ground connection, and avoid placing high-current switching paths adjacent to receiver inputs. The available product listing reports a 7 kΩ input resistance, so cable termination and input-biasing decisions should account for that loading. This page consolidates verified distributor information, package details, practical application guidance, and cross-reference results for the MC1489P. It also distinguishes documented pin-compatible alternatives from parts that are merely functionally similar, helping engineers make package and footprint decisions before committing to a replacement.
MC1489PG - Quad EIA-232D Receiver | onsemi | 14-PDIP
The onsemi MC1489PG is a monolithic quad line receiver designed for EIA-232D data-terminal and data-communication interfaces, with four receiver channels and a 3.0 kΩ to 7.0 kΩ input resistance in a 14-pin PDIP package. The 0.300-inch, 7.62 mm package supports conventional through-hole PCB layouts and provides a direct interface between RS-232 line signals and digital logic systems. An EIA-232D line receiver is an interface IC that converts bipolar RS-232 signal levels into logic-compatible signals for digital equipment. The receiver belongs to the RS-232 interface hierarchy, where transceivers combine receive and transmit functions and line drivers provide the complementary output stage. A quad receiver integrates four independent channels in one package, reducing component count and simplifying parallel serial-interface designs. The MC1489PG provides four EIA-232D receivers, an input resistance specified from 3.0 kΩ to 7.0 kΩ, and a 14-pin PDIP package. Each channel includes a response-control function in the device family architecture, allowing the receiver to be enabled or disabled according to the surrounding interface design. The through-hole package also makes the device suitable for legacy industrial, telecommunications, instrumentation, and control systems where plated-through-hole assembly remains common. The monolithic construction places four receiver sections on one semiconductor device and standardizes the electrical interface for EIA-232D equipment. Input impedance limits the loading applied to the connected RS-232 source, while the receiver threshold determines whether a differential line voltage is interpreted as a valid logic state. Designers should use the manufacturer datasheet pin-description table and operating-limit tables when assigning inputs, response-control terminals, supply connections, and ground returns. Typical uses include multi-channel RS-232 data acquisition, industrial console links, equipment-control interfaces, legacy serial adapters, and embedded systems that communicate with older peripherals. The four-channel arrangement is especially useful when a system exchanges several independent RS-232 signals or requires a receive-only interface alongside a separate line-driver device. When laying out the PCB, route the four receiver inputs away from switching nodes and place interface protection close to connector entries. Confirm the receiver enable state during reset, keep ground returns short, and test every unused channel for a defined logic level. The DIP footprint simplifies through-hole assembly, but the 7.62 mm pin pitch still requires adequate spacing for soldering and connector routing. This product page combines the verified MC1489PG identification, package information, EIA-232D function, receiver count, input-resistance range, source links, and technically constrained replacement analysis to support component selection, board review, sourcing, and design-in decisions.
MC33121P - Low-Voltage SLIC Interface | Motorola | PBX
The Motorola MC33121P is a low-voltage Subscriber Line Interface Circuit (SLIC) designed to connect the four-wire side of a central office or PBX to a two-wire subscriber line in a 14-pin plastic DIP package. It provides battery feed, loop-termination AC impedance, hookswitch detection, adjustable transmit, receive, and transhybrid gains, and single or double fault indication. The verified MC33121P listing identifies a 14-PDIP package, while the available technical material specifies a minimum longitudinal balance of 58 dB. A Subscriber Line Interface Circuit, or SLIC, is an integrated telecommunications interface that replaces many discrete functions associated with a analog telephone line. In the broader hierarchy, it is a specialized line interface IC within interface ICs and telecommunications semiconductors. It bridges a central-office or PBX voice path and a subscriber loop while separating transmit and receive signals, supporting line termination, and exposing hookswitch and fault information to the surrounding codec or control electronics. The MC33121P integrates several line-facing functions into one device. Battery feed supplies the line, while proper loop termination establishes the intended AC impedance seen by the subscriber. Adjustable transmit, receive, and transhybrid gains allow the surrounding system to control voice-path levels and balance. Hookswitch detection reports line activity, and separate status outputs indicate single or double faults, reducing the number of external discrete monitoring elements. Transmit and receive signals are referenced to analog ground, while digital status and control signals are referenced to digital ground. This separation simplifies interconnection with codecs, filters, and digital control logic. The hookswitch and fault outputs are compatible with TTL/CMOS, and the power-down input permits local shutdown. These interface features make the MC33121P suitable for integrated access, subscriber-line, PBX, voice codec, and central-office interface designs. Typical uses include a PBX line card, a central-office subscriber interface, a two-wire telephone-line interface, a voice codec interface, a hookswitch monitor, and a line-fault indication circuit. In each case, the IC provides the physical subscriber-line interface while external circuitry handles codec conversion, call control, supervision, and system-level power management. Because this legacy device is a through-hole 14-pin DIP, it is most practical for legacy designs, repair assemblies, and industrial or telecommunications equipment that can accommodate through-hole leaded components. Designers should preserve separate analog and digital grounding paths and connect the device to the selected codec, filter, and line-conditioning network exactly as shown in the manufacturer application material. Before production use, verify the unavailable operating voltage, temperature range, loop-current limits, external-component values, and absolute maximum ratings against the manufacturer datasheet. Those parameters are not supplied in the verified excerpts and therefore cannot be safely inferred. This page consolidates verified distributor pricing, package information, interface functions, comparison fields, and practical implementation cautions. It also distinguishes documented MC33121P characteristics from unverified alternatives, avoiding unsupported claims that a different SLIC is truly pin-to-pin compatible.
MC33199D - ISO 9141 Automotive K-Line Interface | NXP
The NXP MC33199D is an ISO 9141 automotive diagnostic serial interface circuit with one driver and one receiver, designed for a 4.5 V to 5.5 V supply and packaged in a 14-SOIC. The device connects a vehicle microcontroller to the special K and L lines of an ISO diagnostic port. It provides a bidirectional K-line driver, an L-line receiver used during wake-up sequences, short-circuit protection for the K line, and over-temperature protection. An ISO 9141 interface is a dedicated diagnostic communication interface within the broader automotive network. ISO 9141 uses separate K and L conductors rather than a conventional multidrop CAN bus. The K line carries the main diagnostic communication waveform, while the L line helps establish the wake-up sequence. The MC33199D functions as the physical-layer interface between a microcontroller UART and these vehicle-network lines. Key specifications include 1 driver and 1 receiver, a 4.5 V to 5.5 V operating supply range, ISO 9141 protocol support, and a 14-SOIC package measuring 3.90 mm wide. The K-line driver is bidirectional and protected against short circuits and excessive temperature. The L-line receiver supports the diagnostic wake-up sequence, allowing the host controller to recognize and respond to bus activity. The MC33199D simplifies implementation of an ISO 9141 diagnostic port because the MCU can communicate through ordinary serial logic levels while the IC handles the vehicle K and L lines. Its single-driver, single-receiver arrangement is appropriate for one diagnostic channel. Protection of the K-line output reduces the risk of damage from an inadvertent bus short, although the external vehicle wiring, pull-up network, connector, and transient environment still require careful engineering. Typical applications include automotive diagnostic interfaces, engine-control units, transmission controllers, body-control modules, garage-door and service-tool testers, and other embedded systems that emulate or access ISO 9141 diagnostic ports. The device is most appropriate for legacy diagnostic systems rather than new designs centered on CAN, CAN FD, or LIN. When designing around the MC33199D, verify the K-line and L-line interface network, supply decoupling, grounding, and protection required by the vehicle platform. The 5 V supply range excludes direct 3.3 V operation. Because the part is identified as obsolete in the available replacement information, engineers should also evaluate the NXP-recommended MC33660B replacement against footprint, protocol, timing, and protection requirements before committing to a redesign. This product summary consolidates the verified protocol, electrical, package, lifecycle, replacement, pricing-reference, and design information for engineers evaluating the MC33199D. It also distinguishes verified values from specifications that require confirmation from the manufacturer datasheet, avoiding unsupported assumptions about pin assignments or unqualified substitutes.
MC33290D - ISO 9141 K-Line Serial Link Interface | NXP
The NXP (formerly Freescale) MC33290D is an ISO 9141 K-Line serial link bus interface IC housed in an 8-pin SOIC package, designed for bidirectional half-duplex communication between a vehicle's on-board microcontroller and off-board diagnostic equipment. The device is specified for an 8 V to 18 V supply range, with internal bus driver protection against sustained shorts and overtemperature conditions, and operates across -40 C to +125 C ambient temperature typical of under-hood automotive environments. An ISO K-Line transceiver is a specialized automotive interface device that converts logic-level UART signals into a single-wire, current-driven bus waveform compliant with the ISO 9141 physical-layer definition. Within the broader hierarchy, K-Line transceivers sit below CAN/LIN transceivers and above raw UART bridges as a legacy but still-required physical layer for emissions-related OBD-II communication defined by CARB and EU regulatory frameworks. Key features include a single-wire K-Line bus driver capable of sourcing and sinking bus current, internal thermal shutdown with hysteresis, integrated bus short-to-ground and short-to-battery protection on the bus pin, a wide operating voltage range to tolerate automotive load-dump transients, and a logic-level RX/TX interface that connects directly to a microcontroller UART. The IC's diagnostic mode draws minimal current when the bus is recessive, preserving quiescent power on always-on battery paths. Architecturally, the MC33290D integrates a high-side driver and a low-side driver on the K-Line bus pin, with a comparator-based receiver that distinguishes dominant (logic 0) and recessive (logic 1) bus states. A charge pump is not required because the device operates from the vehicle's nominal 12 V supply, simplifying BOM and PCB area. Typical applications include OBD-II diagnostic interfaces, scan-tool interfaces in service-bay equipment, ECU flashing stations, body controllers communicating with diagnostic testers, and aftermarket telematics units reading ECU K-Line parameters. A key design consideration is that the K-Line bus pin must be terminated with an external pull-up resistor to VBAT and protected against reverse battery by an external diode or smart power path. This is optional: the IC already includes internal bus protection, but external TVS diodes are recommended for production hardware. This page consolidates distributor pricing, drop-in alternatives, and design notes not found in the manufacturer datasheet to accelerate part selection for automotive diagnostic designs.