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P3A1604UKAZ - 4-Bit Dual-Supply Level Translator 40Mbps | NXP
The NXP P3A1604UKAZ is a 4-bit, dual-supply translating transceiver with auto direction sensing, delivering bidirectional voltage level translation at up to 40 Mbps in a 12-pin WLCSP package measuring just 1.06 x 1.41 mm. It operates from VCCA 0.72 V to 1.98 V on the low-voltage side and VCCB 1.62 V to 3.63 V on the high-voltage side, supporting I3C, I2C, SMBus, and SPI interfaces. A voltage level translator (also called a level shifter or translating transceiver) is an interface IC that lets digital devices running at different supply rails communicate safely. In the system hierarchy, it sits in the signal-interface layer between an SoC or MCU and its peripherals, bridging advanced low-voltage process nodes to legacy 1.8 V, 2.5 V, or 3.3 V logic without damaging either side. Key differentiating features include auto direction sensing, which eliminates the DIR control pin required by conventional transceivers - a major benefit for shared bidirectional buses such as I2C and I3C where direction changes dynamically. The wide 0.72 V VCCA floor supports cutting-edge 0.8 V and 1.0 V core-domain SoCs. Four independent channels with up to 40 Mbps throughput cover both slow open-drain buses and fast push-pull SPI lines in one package. Architecturally, the P3A1604UK uses a dual-supply translating transceiver topology in which each channel senses the driving side automatically and reproduces the logic level on the opposite rail. This makes it suitable for mixed-voltage point-to-point and multidrop links between modern ASICs fabricated on advanced nodes and peripheral ICs still powered from higher rails. Typical applications include I3C sensor buses in smartphones and wearables, I2C/SMBus management links in servers, SPI connections between low-voltage MCUs and 3.3 V flash or displays, and portable battery-powered systems where the tiny WLCSP footprint and low power consumption matter. Design consideration: because the WLCSP ball pitch is extremely fine, PCB land pattern accuracy and solder-mask design must follow the manufacturer datasheet recommendations precisely; verify VCCA never exceeds VCCB-side sequencing constraints during power-up. This page synthesizes distributor pricing, lifecycle data, and application guidance not consolidated in the manufacturer datasheet.
PCA82C251T - 24V CAN Transceiver, 1MBd, SOIC-8 | NXP
The NXP PCA82C251T is a legacy CAN (Controller Area Network) bus transceiver that serves as the physical interface between a CAN protocol controller and the differential CAN bus, operating at data rates up to 1 MBd in 24V automotive and industrial systems. Housed in an 8-pin SOIC (SO-8) surface-mount package, it provides differential transmit capability to the bus and differential receive capability to the CAN controller, with full conformance to the ISO 11898-24V standard for 24V systems used in trucks, buses, and heavy industrial vehicles. A CAN transceiver is a physical-layer (PHY) device that converts the single-ended digital transmit (TXD) and receive (RXD) signals from a CAN protocol controller into the differential dominant/recessive signaling required by the CAN bus. It sits between the protocol controller (an MCU with a CAN module) and the twisted-pair bus, providing the drive strength, common-mode rejection, and bus-fault protection needed for robust communication. The PCA82C251 belongs to the broader family of CAN transceivers and is part of the NXP (formerly Philips Semiconductors) automotive connectivity portfolio. Key features of the PCA82C251T include a maximum data rate of 1 MBd, wide supply voltage range of 4.5V to 5.5V (typical 5V), bus terminals tolerant to -27V to +40V transients, low current consumption in standby and recessive states, thermal shutdown protection, and current limiting on the bus outputs. The device operates over the -40C to +125C automotive temperature range, making it suitable for under-hood applications and other harsh industrial environments. It is supplied in the industry-standard 8-pin SOIC (SO-8) package for reflow-soldered surface-mount assembly. The PCA82C251T uses a bipolar CMOS process with on-chip bus-driver protection and slope-control circuitry to limit RFI emissions. Its high-impedance bus input during supply loss prevents the device from loading the bus when unpowered, supporting multi-node hot-swap scenarios. Compared to lower-voltage CAN transceivers, the 24V-tolerant bus pins make this part specifically suited for trucks, buses, agricultural machinery, and industrial CAN networks powered from 24V rails where common-mode transients exceed the range of 12V-only parts. Typical applications include 24V truck and bus CAN networks, agricultural and construction equipment CAN buses, industrial automation CANopen networks, forklift and material-handling vehicle communication, and CAN-based battery management in 24V lead-acid battery stacks. The ISO 11898-24V conformance also makes it a candidate for heavy-duty on-road and off-road vehicle communication backbones. When designing with the PCA82C251T, note that it is a legacy part and the modern TJA1051T, TJA1042T, or TJA1057T from NXP offer lower quiescent current, faster loop times, and improved EMC behavior for new designs. Engineers should select a 24V-rated replacement only when pin-compatibility or bus-fault tolerance is critical; the standard 12V TJA1050T is NOT a drop-in because its bus common-mode range is narrower and will not survive 24V-system transients. This page synthesizes distributor pricing, verified drop-in alternatives (same-brand and cross-brand in SOIC-8), practical design notes, and a parameter comparison table not bundled together on the manufacturer's product page.
PCA82C251T-YM118 - 24V CAN Transceiver, 1Mbps, SOIC-8 | NXP
The NXP PCA82C251T-YM118 is a legacy CAN bus transceiver for 24 V systems, providing the physical interface between a CAN protocol controller and the differential CAN bus. Housed in an 8-pin SO (SOIC-8) surface-mount package, it supports data rates up to 1 Mbps and operates from a single 5 V supply (4.5 V to 5.5 V), with bus pins tolerant to ±27 V of common-mode voltage for harsh 24 V automotive and industrial environments. A CAN transceiver (Controller Area Network transceiver) is a physical-layer device that converts the digital transmit/receive logic of a CAN protocol controller into the differential voltage signaling required by the CAN bus standard (ISO 11898). Within the broader system hierarchy, a CAN transceiver sits between the protocol controller (MCU) and the physical wiring harness, and belongs to the family of differential line drivers / interface ICs / wired-connectivity semiconductors. The 82C251 is the third-generation "PCA82C251" device, designed for 24 V truck and bus applications and predates the modern TJA1050 / TJA1042 / TJA1051 family. Key features include ±27 V bus fault protection on CANH and CANL, thermal shutdown with automatic recovery, a current-limited transmitter for short-circuit protection on the bus, and a low-current standby mode (typ. 275 µA supply current per Mouser listing). The differential receiver provides high common-mode rejection, and the driver stage supports slew-rate-limited transmission at speeds up to 1 Mbaud. The device exposes TxD, RxD, VCC, GND, CANH, CANL, Vref, and Rs pins on the SO-8 footprint. The architecture uses a bipolar process optimized for high bus voltage tolerance, with on-chip protection diodes clamping transient voltages beyond the supply rails. The Rs pin selects between high-speed, slope-control, and standby modes, providing a software/hardware mechanism for EMC tuning or low-power operation when the bus is idle. Typical applications include 24 V truck and bus CAN nodes, industrial CANopen networks, automotive body and chassis ECUs, agricultural machinery telemetry, and marine electronics. It is a pin-compatible second-source for the legacy PCA82C251 footprint, useful when modern 12 V TJA parts are not suitable. When designing with this part, place a 100 nF decoupling capacitor close to the VCC pin and use a split termination (60 Ω + 60 Ω + 100 nF to ground) at each end of the CAN bus for proper 24 V signal integrity. The Rs pin mode selection must be configured via a resistor to ground or to VCC; leaving it floating is not recommended. The PCA82C251T is marked NRND by NXP - prefer the TJA1051T or TJA1057T for new designs, but this part remains in production for legacy 24 V applications. This page synthesizes distributor stock, parametric data, drop-in second sources, and application guidance drawn from NXP's PCA82C251 datasheet plus current distributor inventory, not all of which appears in a single manufacturer PDF.
PCA82C251T/N3,118 - 24V CAN Transceiver SOIC-8 | NXP
The NXP PCA82C251T/N3,118 is the interface between a CAN protocol controller and the physical bus, primarily intended for applications up to 1 MBaud in 24 V truck and bus systems. It provides differential transmit capability to the bus and differential receive capability to the CAN controller and is fully compatible with the ISO 11898-24 V standard. The /N3,118 suffix denotes the SOIC-8 (D-package) tape-and-reel delivery option used for high-volume automated assembly. A CAN transceiver (Controller Area Network transceiver) is a physical-layer IC that converts the digital transmit (TXD) and receive (RXD) signals of a CAN protocol controller into the differential CANH and CANL bus signals, and vice versa. Within the broader hierarchy, a CAN transceiver is a type of bus transceiver, which is a type of interface IC, which sits inside the Interface ICs category of integrated circuits. The PCA82C251 family targets 24 V automotive and industrial systems where high bus robustness and good electromagnetic compatibility are required. Key features include a -27 V to +40 V bus fault tolerance on CANH/CANL, thermal shutdown protection, current limiting on the transmitter outputs, and a slope-control pin that lets the user programme the bus rise/fall time. The IC operates from a single 4.5 V to 5.5 V supply, draws a typical quiescent current of 16 mA in recessive mode, and survives automotive transients on the bus lines. The SOIC-8 plastic package offers a small PCB footprint with a standard 1.27 mm pin pitch. Typical applications include 24 V truck and bus CAN nodes, industrial CANopen networks, agricultural and construction machinery, and any 12 V or 24 V CAN bus node requiring the classic PCA82C251 silicon. The PCA82C251 is the second-generation PCA82C250 follow-on and is widely second-sourced across the industry. Note that NXP has moved this part to NRND (Not Recommended for New Designs) - new designs should evaluate TJA1043, TJA1051, or TJA1042 for similar 24 V capability. When designing with this part, place a 100 nF decoupling capacitor as close as possible to pin 8 (VCC) and follow the ISO 11898 bus termination of 120 Ω at each end of the bus. The slope-control resistor on pin 8 (Rs) must be chosen against the desired bit rate; for 1 MBaud operation NXP recommends tying Rs to ground, while for lower bit rates a larger resistor reduces EMI. This page synthesises distributor stock, drop-in equivalents, and design guidance not found in the standalone datasheet PDF.
PCA82C251T/YM,112 - CAN Transceiver for 24V Systems | NXP
The NXP Semiconductors PCA82C251T/YM,112 is a legacy Controller Area Network (CAN) transceiver for 24 V systems, supplied in an 8-pin SOIC package (SOT96-1 / SO-8). The device provides a single differential transmit driver and a single differential receiver, providing the physical interface between a CAN protocol controller and the differential CAN bus. It operates from a single 4.5 V to 5.5 V supply, supports data rates up to 1 Mbaud, and is fully compatible with the ISO 11898-24 V standard. What is a CAN transceiver? A CAN transceiver (Controller Area Network transceiver) is a physical-layer interface IC that bridges a digital CAN protocol controller — typically a microcontroller with a built-in CAN module — and the differential CAN bus wiring found in vehicles, industrial equipment, and factory automation systems. Within the broader semiconductor hierarchy, a CAN transceiver belongs to the Interface ICs family, which sits inside the Integrated Circuits product tree. It is the companion IC to a CAN controller, the safety/transceiver side of an automotive/industrial bus, providing the differential drive strength, common-mode tolerance, and bus-fault robustness that digital logic alone cannot deliver. Key features of the PCA82C251T/YM,112 include slope-control to reduce Radio Frequency Interference (RFI), thermal shutdown protection, short-circuit protection on the bus pins, and an exposed thermal pad-friendly SO-8 footprint. The transceiver provides recessive and dominant bus states compliant with ISO 11898-24 V, can detect a permanent dominant condition on the bus, and includes a low-current standby mode controlled via the Rs (slope / standby) pin. The bus pins (CANH, CANL) survive load-dump transients encountered in 12 V and 24 V automotive/industrial environments, making the part the workhorse interface for truck, bus, agricultural, and off-road vehicle networks. Internally, the PCA82C251T/YM,112 uses a bipolar transmitter architecture with a precision differential output stage. The slope-control pin (pin 8) lets the designer trade edge rate against RFI; slower edges reduce emissions on unshielded bus cabling at the cost of maximum achievable bit rate. The receiver compares the bus differential voltage against an internal reference with sufficient hysteresis to reject common-mode noise, and the TXD input feeds a dominant/recessive driver that pulls the bus to the ISO 11898-24 V defined levels. A thermal shutdown block protects the output stage against continuous short circuits on CANH or CANL. Typical applications include in-vehicle CAN networks for trucks, buses and agricultural machinery, industrial automation CAN nodes, building automation (HVAC, lifts), and any 24 V battery-powered CAN segment requiring compliance with ISO 11898-24 V. Designers pair the PCA82C251T/YM,112 with microcontrollers that include a CAN controller (such as NXP LPC, S32K, or Kinetis families) and external protection components (TVS diodes, common-mode chokes) on the bus side. When designing with this transceiver, fit a split-termination network (typically 60 Ω total with a 10 nF to 100 nF capacitor to ground) close to the bus pins to match the cable impedance and improve EMC. Slope-control resistance should be chosen to keep edge times short enough for the target baud rate while still meeting automotive EMC limits. Ensure the supply is decoupled with a 100 nF ceramic capacitor placed within a few millimeters of the VCC pin. This page synthesizes NXP datasheet specifications, distributor pricing as of 2026-10-13, drop-in alternatives (same-brand first, then cross-brand), and practical design notes not found in the standalone datasheet to give engineers an actionable component reference.
PCA8574D,512 - 8-Bit I2C I/O Expander 400kHz SOIC-16 | NXP
The NXP PCA8574D,512 is a remote 8-bit I/O expander for the I2C-bus with interrupt output, providing eight quasi-bidirectional general-purpose I/O lines in a 16-pin SOIC (SO16) package. It operates from a single 2.3V to 5.5V supply, supports the Fast-mode 400 kHz I2C bus, and offers three hardware address pins (A0, A1, A2) plus an open-drain active-low interrupt output. An I2C I/O expander is a type of interface IC that lets a microcontroller control additional digital inputs and outputs through the two-wire serial bus (SCL and SDA), reducing the number of GPIO pins the MCU itself must provide. Within the interface IC hierarchy, the PCA8574 sits alongside I2C multiplexers, port expanders and level translators, and is a direct successor in function to the industry-standard PCF8574. Key features include eight quasi-bidirectional ports that can be independently assigned as inputs or outputs, a 400 kHz I2C-bus interface, low standby current of approximately 10 uA, an latched outputs architecture with power-on reset, and an open-drain INT output that notifies the host of any input change. The quasi-bidirectional I/O structure allows a pin to be used as input or output without direction-control registers, simplifying firmware. The three hardware address pins allow up to eight PCA8574 devices (or eight PCA8574A devices with the alternate fixed slave address) on one bus, supporting up to 16 expanders and 128 I/Os, for example 128 LEDs, from a single two-wire bus. Latched outputs directly drive LEDs with high current sink capability. Typical applications include keypads and switch matrices, LED and indicator driving in white goods and industrial control panels, SPDT relay expansion, sensor monitoring in battery-powered products, and remote I/O expansion in automotive body electronics. For design, remember the quasi-bidirectional ports sink strongly but source only weakly (approximately 100 uA at VDD = 5V), so use external pull-ups on input lines and drive LEDs in sink mode. This page synthesizes distributor pricing, verified drop-in alternatives, practical design notes, and EOL lifecycle guidance not found in the manufacturer datasheet alone.
PCA8574D-T - 8-Bit I2C I/O Expander 400kHz | NXP
The NXP PCA8574D-T is a remote 8-bit I/O expander for the I2C-bus with interrupt output, housed in a 16-pin SO16 (SOIC) package, operating at up to 400 kHz Fast-mode I2C. It provides general-purpose quasi-bidirectional I/O expansion for most microcontroller families via the two-line bidirectional I2C-bus (serial clock SCL and serial data SDA). An I/O expander is a type of interface IC within the broader hierarchy of interface and connectivity semiconductors. It allows a microcontroller with limited GPIO pins to control additional digital inputs and outputs over just two bus lines, reducing pin count, board space, and wiring complexity. I/O expanders are common companions to MCUs such as those from NXP, STMicroelectronics, and Microchip in embedded systems. Key features of the PCA8574D include an 8-bit quasi-bidirectional port with latched outputs, an open-drain interrupt (INT) output that alerts the host controller to remote input changes, and three hardware address pins (A0, A1, A2) that allow up to eight PCA8574 devices on the same I2C-bus. Combined with the PCA8574A variant (different fixed slave address), up to 16 devices can share one bus, supporting up to 128 I/Os, for example driving 128 LEDs. Architecturally, the device integrates an 8-bit quasi-bidirectional I/O port, an I2C-bus slave interface with Fast-mode 400 kHz support, and power-on reset logic that sets all ports to a defined state at startup. The quasi-bidirectional structure means each pin can serve as input or output without a direction-control register, simplifying firmware. Typical applications include keypad scanning and keyboard interfaces, LED and indicator driving, backplane status monitoring in industrial systems, and general-purpose GPIO expansion in automotive body electronics and consumer appliances. Design consideration: quasi-bidirectional pins source a weak holding current when set high, so external loads must sink current to pull a pin low; check sink capability per the manufacturer datasheet before driving heavier loads. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
PCA8575PW,118 - 16-bit I2C I/O Expander TSSOP-24 | NXP
The NXP Semiconductors PCA8575PW,118 is a remote 16-bit I/O expander for the I2C-bus (SCL/SDA), providing a 16-bit quasi-bidirectional parallel port and an interrupt output, housed in a 24-pin TSSOP (4.4 mm body width) surface-mount package and supplied on Digi-Reel. The device supports a supply range of 2.3 V to 5.5 V and operates at an I2C clock frequency up to 400 kHz (Fast-mode), making it drop-in compatible with the wide majority of 3.3 V and 5 V microcontroller I2C peripherals. An I/O expander is a bus-attach peripheral that multiplies a host controller's general-purpose I/O count by adding parallel input/output pins over a serial link. The PCA8575PW,118 belongs to the I2C-bus I/O expander family (I/O expander -> GPIO expander -> parallel I/O port -> interface IC -> integrated circuit). Quasi-bidirectional outputs can be driven low actively by the device or pulled high weakly, which lets a single pin directly sink LED current when configured as an output and still be read as a logic high when the external driver releases the line - useful for keypad scanning and switch-matrix polling. Key features include 16 individually addressable I/O lines, an open-drain interrupt (INT) line that asserts when any input changes state, three hardware address pins (A0/A1/A2) allowing up to eight devices on one bus (128 I/O total), latched outputs with high-current drive capability suitable for direct LED driving, and a low standby current that suits battery-powered designs. The integrated address decoder, input filter, and edge-triggered interrupt block reduce host firmware overhead because the MCU only services the PCA8575PW,118 when an actual port event occurs. Typical applications include adding pushbuttons, keypads, LED indicators, relay drivers, and sensor multiplexing to 8-pin microcontrollers, white-goods and appliance front panels, industrial PLC I/O modules, and PC accessory sideband ports. The 400 kHz Fast-mode I2C clock and 2.3 V to 5.5 V supply let it interface directly with 3.3 V ARM Cortex-M parts and 5 V legacy MCUs without level translation. When designing with this device, place the standard 100 nF VCC bypass within 5 mm of the supply pin and add 10 kohm pull-ups on SDA and SCL - quasi-bidirectional outputs still require external pull-ups to drive logic high reliably. Reserve the INT pin for an MCU edge-triggered input and avoid tying it permanently high; the address pins A0-A2 must be tied to a fixed logic level and not left floating at power-up. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the NXP datasheet alone, including the comparison and pinout data that engineering teams need to qualify a second source.
PCA9306H - Dual I2C/SMBus Voltage-Level Translator | TI
The Texas Instruments PCA9306H is a dual bidirectional I2C-bus and SMBus voltage-level translator with an enable (EN) input, operating from 1.2 V to 3.3 V on VREF1 and 1.8 V to 5.5 V on VREF2, housed in an 8-pin VSSOP (DCT) package. It translates between two voltage domains without a direction pin, making it a compact solution for mixed-voltage I2C and SMBus networks. A voltage-level translator is an interface IC that safely connects digital signals operating at different supply voltages, for example a 1.8 V microcontroller I2C peripheral talking to a 3.3 V or 5 V sensor. Within the signal-chain hierarchy, the PCA9306H belongs to the level-translator family of interface ICs, positioned alongside I2C buffers, repeaters, and multiplexers. Because I2C is an open-drain bus, translation requires a bidirectional pass element rather than a directional buffer - exactly the architecture this device implements. Key features include directionless bidirectional translation, an enable pin that puts both switch channels into a high-impedance state when LOW, and low ON-state resistance of the pass FET, which keeps propagation delay minimal. The wider VREF1 range of the PCA9306H (1.2 V to 3.3 V, versus 1.0 V to 3.6 V or lower-floor variants in the family) makes it suitable for modern low-voltage processors. It supports standard-mode (100 kHz), fast-mode (400 kHz), and fast-mode plus (1 MHz) I2C devices as well as SMBus systems. Architecturally, the device is a pair of N-channel pass transistors with gate drive referenced to EN and the reference supplies. When EN is HIGH, SDA1/SCL1 connect to SDA2/SCL2; pulling either side low through its open-drain pull-up propagates the low to the other side, achieving the gate-threshold offset that produces the voltage shift. Because there is no active buffering, signal integrity is essentially transparent, with propagation delay dominated only by the switch Ron and external pull-up resistors. Typical applications include connecting 1.8 V MCUs to 3.3 V or 5 V sensors and EEPROMs, translating between 3.3 V SMBus hosts and lower-voltage peripherals in servers and networking cards, and interfacing low-voltage FPGA or SoC I2C banks to 5 V legacy buses in industrial control systems. For reliable operation, size the pull-up resistors on both sides of the translator according to the bus speed and bus capacitance; each side must have its own pull-up. Also note the 200 kOhm internal pass-gate resistance behavior at low VREF2 voltages when calculating rise times. This page synthesizes distributor data, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
PCA9306USG - Dual I2C/SMBus Voltage-Level Translator | onsemi
The onsemi PCA9306USG is a dual bidirectional I2C-bus and SMBus voltage-level translator with an enable (EN) input, operating from 1.2 V to 3.3 V VREF1 and 1.8 V to 5.5 V VREF2, delivering 1.5 ns typical propagation delay and 3.5 ohm ON-state resistance in an 8-pin VSSOP (US8) package. A voltage-level translator is an interface IC that allows devices operating at different supply voltages - for example a 1.8 V microcontroller and a 5 V sensor - to share the same two-wire bus safely. Within the signal-chain hierarchy, level translators sit in the interface IC family alongside I2C multiplexers, buffers, and repeaters. The PCA9306 belongs to the switch-based (passive) translator class: it uses two N-channel pass transistors per channel rather than active output stages, so the bus is pulled up naturally by the resistors on each rail. Key features include bidirectional voltage translation between 1.2 V and 5 V with no direction pin, support for Standard-mode (100 kbps), Fast-mode (400 kbps), and Fast-mode Plus (1 Mbps) I2C-bus plus SMBus operation, a very low 3.5 ohm ON-state connection that minimizes signal distortion, and an active-high EN input that isolates both buses when the translator is not needed. The 1.5 ns rise/fall propagation characteristic keeps bus timing margin intact even at Fast-mode Plus speeds. The switch architecture means the PCA9306 introduces virtually no drive strength of its own - the 64 mA figure refers to the pass-transistor current handling capability. Because it is a passive switch, lock-up free operation is guaranteed even during bus contention or partial power-down, a known failure mode of active level-shifter designs. Both SDA and SCL channels are identical, so the device handles the full 2-bit I2C bus in a single package. Typical applications include connecting 1.8 V to 3.3 V microcontrollers to 5 V I2C sensors and EEPROMs, level-shifting SMBus rails in server power supplies, battery-powered portable systems where two rail domains must communicate, and mixed-voltage industrial control modules. Design consideration: the EN pin must be driven above the higher VREF2 rail to guarantee the pass gates turn fully on; always provide pull-up resistors on both sides of each channel sized for the respective rail. This page synthesizes distributor cross-reference data, drop-in alternatives, and practical design notes not found in the manufacturer datasheet. Pricing as of 2026-10-19.
PCA9507DP,118 - 2-Wire Bus Extender, 5V, 8-TSSOP | NXP
The NXP PCA9507DP,118 is a 2-wire serial bus extender with integrated 3.3 V to 5 V level shifting, one bidirectional I²C/SMBus channel, and a 400 kHz maximum clock rate, packaged in an 8-pin TSSOP (SOT505-1, DP suffix). It provides bidirectional buffering of SDA and SCL lines while preserving all I²C operating modes (master/slave, multi-master, arbitration) across the level-shift boundary, and it extends the usable bus length up to 18 meters for HDMI DDC, I²C-bus, and SMBus links. The device operates from a 2.7 V to 5.5 V supply and is specified across the -40 °C to +85 °C industrial temperature range. What is an I²C bus extender? An I²C bus extender (also called a bus repeater or accelerator) is a type of interface IC that sits between two segments of a 2-wire serial bus and buffers both SCL (clock) and SDA (data) lines. Its purpose is twofold: to overcome capacitive loading limits that cap I²C bus length, and to translate voltage levels between dissimilar supply domains. The PCA9507 sits in the broader hierarchy of bus interface ICs (interface IC > bus extender > signal buffer/repeater), and is a specialized sibling of the I²C hub/switch family such as the PCA9543A. Key features of the PCA9507DP,118 include: 1 channel of buffered SDA + SCL; support for Standard-mode (100 kHz), Fast-mode (400 kHz), and 3.4 MHz Fast-mode Plus overshoot tolerant operation on the upstream port; 2.7 V to 5.5 V supply range; 218 ns typical propagation delay; and integrated rise-time accelerators that allow designers to drop the bus pull-up resistors while still meeting rise-time budgets on long cables. It also provides hot-swap insertion tolerance so that cards can be plugged into a live backplane without corrupting the bus. The internal architecture uses two N-channel MOSFET pass gates with charge-pump enhancement, plus direction-sensing comparators that automatically configure the channel as upstream or downstream. The upstream (master-side) port tolerates 3.3 V to 5 V, while the downstream port can operate down to 2.7 V, enabling typical 3.3 V-to-5 V HDMI DDC level shifting. The TSSOP-8 footprint makes the part suitable for compact HDMI connector breakouts, display modules, and embedded backplanes. Typical applications include HDMI/DVI Display Data Channel (DDC) level shifters, I²C-bus extension over long cables (up to 18 m) in industrial control panels, SMBus fan and chassis management links, and any board-to-board 2-wire link that must bridge a voltage-level or capacitive-load gap. Because the device preserves arbitration and clock-stretching behavior, it is safe to insert in the middle of an existing multi-master bus. When designing with the PCA9507, remember that the part is a pure bus extender with no pull-ups on either side. Both upstream and downstream segments still require external pull-up resistors sized to the segment capacitance, and the device's quiescent current (typically a few hundred microamps) must be included in the system power budget. For long cables, place the PCA9507 near the connector to keep the high-impedance stub short. This page synthesizes distributor pricing, same-brand and cross-brand drop-in alternatives, and practical design notes for HDMI DDC and long-cable I²C applications - context not collected in the manufacturer datasheet alone.
PCA9509DP,118 - I2C/SMBus Level Translating Repeater | NXP
The NXP PCA9509DP,118 is a level translating I2C-bus/SMBus repeater that enables a processor low-voltage 2-wire serial bus to interface with standard I2C-bus or SMBus I/O, providing bidirectional buffering for both the SDA (data) and SCL (clock) lines at up to 400 kHz in an 8-pin TSSOP (SOT505-1) package. An I2C repeater (also called a bus buffer or redriver) is an interface IC that regenerates the two-wire serial signals so that capacitive loading and voltage-level differences do not limit bus length or device count. Within the interface-IC hierarchy (repeater -> bus buffer -> I2C/SMBus controller -> communication interface IC), repeaters sit between a low-voltage processor side and a higher-voltage peripheral side, keeping rise times and logic thresholds compliant on both segments. Key features include dual-supply level translation, supporting a low-voltage side and a standard 3 V to 5.5 V bus side, and bidirectional buffering that extends the I2C-bus by isolating capacitance on each segment. The device retains all operating modes and features of the I2C-bus system during level shifts, including clock stretching and multi-master arbitration behavior. A typical propagation delay of 109 ns and a low 2 pF input capacitance keep timing margin comfortable even at the 400 kHz fast-mode ceiling, while 5 mA supply current suits power-conscious designs. Technically, the PCA9509 uses open-drain buffer stages with rise-time acceleration so both bus segments retain true open-drain behavior: contention and backplane noise are not passed between segments, and the parts act as fault isolators between a captive processor bus and a larger peripheral bus. Typical applications include extending I2C from an MCU to backplanes and card cages, level-shifting between 1.x V/1.8 V/2.5 V processors and 3.3 V/5 V SMBus peripherals in servers, telecom line cards, and industrial control panels where bus capacitance would otherwise exceed the 400 pF I2C limit. Design-wise, plan pull-up resistor values per segment: each buffered side requires its own pull-ups sized for that segment's total capacitance, since the repeater isolates the two sides electrically. This page synthesizes distributor pricing, availability data, and practical design guidance not found in the manufacturer datasheet, with all parameters traced to NXP and distributor sources as of 2026-10-20.
PCA9510ADP,118 - Hot-Swap I2C/SMBus Buffer | NXP Semiconductors
The NXP Semiconductors PCA9510ADP,118 is a hot-swappable I2C-bus and SMBus bus buffer that allows I/O card insertion into a live backplane without corrupting the data and clock buses. It is supplied in an 8-pin TSSOP (SOP) surface-mount package and buffers one channel of the two-wire serial bus at operating speeds up to 400 kHz. An I2C bus buffer (also called a bus repeater or redriver) is a two-wire interface IC that sits between an I2C or SMBus controller segment and a downstream segment. Within the interface IC hierarchy - serial interface ICs to buffers/repeaters to logic ICs - its role is to isolate bus capacitance, extend the number of devices or cable length a bus can drive, and protect one segment from faults or transients on the other. The defining feature of the PCA9510A is its hot-swap control circuitry. During card insertion, contact bounce and partial power-up can corrupt SDA and SCL lines; the PCA9510A keeps the backplane side disconnected until a stop command or bus idle condition occurs on the backplane without bus contention on the card side. Only then does it make the bidirectional connection, preserving data integrity on the live backplane. Technically, the buffer provides bidirectional buffering with rise-time acceleration on the output sides, allowing larger bus capacitance than a raw I2C port can tolerate. It supports both the standard I2C-bus and the SMBus (System Management Bus) protocol and operates from a single supply, making it a drop-in isolation element between a backplane and a removable I/O card. Typical applications include live-insertion I/O cards in telecom and server backplanes, CompactPCI-style shelves, SMBus segments in power supplies and battery-backed systems, and any hot-pluggable module that must not disturb an operating two-wire bus during insertion or removal. Design consideration: keep the two bus segments physically separated on the PCB and provide adequate pull-up resistors sized for each segment's capacitance; the buffer does not eliminate the need for correct pull-up values on either side. This page synthesizes distributor pricing context, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet, with all electrical data traced to the NXP PCA9510A product data sheet (Rev. 01, 8 September 2005).
PCA9512AD - Hot-Swap I2C/SMBus Buffer, 3.3V-5V | NXP
The NXP PCA9512AD is a level-shifting, hot-swappable I2C-bus and SMBus buffer housed in an 8-pin SOIC package, providing bidirectional buffering for one channel at up to 400 kHz. It integrates two dedicated supply pins (VCC1 and VCC2) that allow independent 3.3 V and 5 V rails to coexist on the same bus while preserving maximum noise margin on each side. The device prevents backplane data/clock corruption during live card insertion by isolating the precharge voltages of the I/O card from the active backplane rails. An I2C/SMBus buffer is a bus repeater/accelerator that isolates two segments of a multi-drop serial bus, supports level translation between mixed-voltage nodes, and optionally accelerates the rising transitions of the SCL/SDA open-drain lines. Buffers sit between a controller and its peripherals, between two bus segments on a backplane, or between a host and removable card. The PCA9512 family belongs to NXP's broader bus-interface category, positioned between simple repeaters (e.g., PCA9507) and full multi-channel hubs (e.g., PCA9548). Hot-swap capability requires a precharge circuit that gently biases SCL/SDA before the card connector mates, avoiding the inrush glitches that would otherwise corrupt bus traffic. Key features of the PCA9512AD include 3 mA sink capability on each side per the I2C specification, support for bus voltages from 2.0 V to 5.5 V on either supply rail, and compatibility with Standard, Fast, and Fast-Plus (400 kHz) I2C modes. The buffer provides offset voltage between the two bus segments to prevent input-to-output latch-up, and it includes rise-time accelerator circuitry that minimizes bus settling time on heavily loaded segments. The 8-SO package is pin-compatible with the PCA9509 and other 8-pin I2C buffers, simplifying PCB layout reuse. The PCA9512AD is built on NXP's sub-micron CMOS process and uses an internal charge pump to drive the gate of the accelerator FETs, ensuring consistent rise-time performance across temperature. The dual-rail architecture allows designers to mix 3.3 V and 5 V devices on the same physical bus without external level translators, and the offset-impedance design prevents bus contention during simultaneous master access. ESD protection exceeds 2 kV HBM on the SCL/SDA pins. Typical applications include hot-swap I/O cards in telecom base stations, ATCA/cPCI backplane signal buffering, server management buses (IPMB, PMBus), and mixed-voltage I2C sensor aggregation. The device is commonly used where 3.3 V MCUs must communicate with 5 V legacy peripherals on the same bus segment. When designing with the PCA9512AD, ensure that VCC1 and VCC2 decoupling capacitors are placed within 2 mm of their respective supply pins. The offset voltage between bus segments must be accounted for in voltage-margin calculations, and live-insertion sequencing must guarantee that the I/O card's SCL/SDA lines reach the buffered idle state before the connector fully mates. Note: per the NXP product page, the PCA9512AD is End-of-Life, so designers should validate last-time-buy opportunities for production runs. This page synthesizes distributor pricing, drop-in alternatives, and practical design guidance that goes beyond the manufacturer datasheet, helping engineers make informed replacement and supply-chain decisions for this EOL part.
PCA9515ADR - Dual I2C/SMBus Bus Repeater 400kHz | TI
The Texas Instruments PCA9515ADR is a dual bidirectional I2C bus and SMBus repeater (buffer/ReDriver) with 2 channels, supporting up to 400 kHz operation, supplied in an 8-pin SOIC package. It operates from a single 2.3 V to 3.6 V supply and its open-drain I2C I/O pins and enable input are 5.5-V tolerant. An I2C bus repeater is an interface buffer that isolates the capacitance and noise of one segment of an I2C or SMBus from another. Within the signal-chain hierarchy (I2C repeater -> bus buffer -> interface IC -> mixed-signal semiconductor), repeaters let a single controller address far more devices or far longer PCB traces and cables than the ~400 pF bus-capacitance limit would otherwise allow, while keeping rise times compliant. Key features include two identical bidirectional open-drain buffer channels, an active-high repeater-enable input (EN) for power-up isolation and bus segmentation, 5.5-V tolerant I2C I/O and EN for mixed-mode 3.3 V/5 V operation, and lockup-free operation that accommodates the clock-stretching and arbitration behavior of multi-master I2C systems. Technically, the PCA9515A is fabricated in a BiCMOS process. Each buffer uses a rising-edge accelerator and direction-sensing scheme that distinguishes a master-driven LOW from a slave-driven LOW, preventing the input-to-output latch-up that plagued first-generation repeaters. Because both channels are identical, the device can be used as two independent 1-bit repeaters or as a single 2-bit bus switch-style buffer. Typical applications include I2C bus segment isolation in servers and telecom cards, capacitive load expansion on long backplanes and cables, level-tolerant buffering between 3.3 V controllers and 5 V legacy peripherals, and SMBus systems in power-management and battery-pack designs. A key design consideration: the buffer is unidirectional-gain per edge, so it must not be used in loops or back-to-back without careful segmentation; place it where the bus capacitance exceeds roughly 400 pF or when isolating a noisy or fault-prone slave segment. This page adds value beyond the datasheet by synthesizing distributor pricing, verified drop-in alternatives, comparison tables, and practical layout guidance in one place.
PCA9527DP - 3-Ch HDMI DDC/CEC I2C Bus Buffer | NXP
The NXP Semiconductors PCA9527DP is a 3-channel bidirectional open-drain bus buffer for HDMI Display Data Control (DDC) clock, data and Consumer Electronic Control (CEC), operating at up to 400 kHz from a 2.7 V to 5.5 V supply in a 10-pin TFSOP (10-TSSOP) package. A bus buffer (also called a bus extender or repeater) is a signal-conditioning device inserted between a master and a slave on a two-wire serial bus such as I2C-bus, SMBus or HDMI DDC. It belongs to the broader family of interface ICs and signal buffers, repeaters and splitters. Its role is to isolate bus capacitance on either side, so each segment sees only its own load, allowing longer cables and more devices than the raw bus standard permits. Key features of the PCA9527 include three independent bidirectional channels for SDA, SCL and CEC, support for the full 400 kHz Fast-mode I2C-bus operating range, and overvoltage-tolerant SDAx and SCLx pins. Propagation delay is a low 115 ns and input capacitance is only 8 pF, preserving setup and hold margins on long HDMI DDC cables. Architecturally, the PCA9527 uses open-drain bidirectional buffer stages with rise-time acceleration (buffer accelerator) circuitry. This rising-edge accelerator drives the bus high actively, compensating RC charging losses across long DDC lines while retaining all operating modes of the I2C-bus system during level shifting. According to the NXP datasheet, using the PCA9527 enables the system designer to isolate bus capacitance to meet the HDMI DDC version 1.3 distance specification. Typical applications include HDMI source and sink equipment (set-top boxes, TVs, monitors, AV receivers) where DDC/CEC lines must traverse cables or backplanes, notebook docking stations, and any system that extends I2C-bus or SMBus segments beyond the standard capacitance limit. The dedicated third channel carries CEC without consuming I2C channels. Design consideration: keep pull-up resistor values on both bus segments sized per segment capacitance; the accelerator helps but very heavy loads on the downstream side still degrade rise times, so verify rise-time compliance at the far end of the HDMI cable. This page adds value beyond the manufacturer datasheet by synthesizing distributor availability data, drop-in replacement guidance for this EOL part, practical design notes, and a comparison table in one place. Note: the PCA9527DP is listed by NXP as End of Life; pricing shown is indicative and all designs should plan a replacement strategy (as of 2026-10-20).
PCA9527DP,118 - 3-Ch I2C/HDMI DDC CEC Bus Buffer | NXP
The NXP PCA9527DP,118 is a 3-channel bidirectional open-drain bus buffer that supports up to 400 kHz I2C-bus operation, operates from a 2.7 V to 5.5 V supply, and provides a typical 115 ns propagation delay, housed in a 10-pin TSSOP (10-TFSOP, 0.118 inch width) package with the ,118 suffix denoting a Tape & Reel, RoHS-compliant shipping option. A bus buffer (also called a bus extender or repeater) is an interface IC inserted in series with a two-wire serial bus such as I2C (Inter-Integrated Circuit) or SMBus (System Management Bus). Within the broader hierarchy of interface semiconductors, bus buffers sit alongside level translators and line drivers, and their role is to segment bus capacitance, regenerate signal edges, and isolate parasitic loading so the bus can be longer or drive more devices than the raw open-drain bus standard would otherwise permit. Key features of the PCA9527 include three independent bidirectional channels dedicated to the HDMI Display Data Channel (DDC) clock and data lines plus the Consumer Electronics Control (CEC) line, support for Fast-mode 400 kHz I2C and SMBus signaling, an active-HIGH EN enable pin with an internal pull-up of approximately 100 kOhm to VCC(B) that places the device in a low-power down state when disabled, and two separate power supply pins that allow voltage level shifting between the two sides of the bus. Technically, the device uses rise-time accelerators on each open-drain channel to actively speed up rising edges that would otherwise be limited by pull-up resistors and bus capacitance. Input capacitance is 8 pF per pin, minimizing loading on the source side, and supply current is specified up to 100 mA. Because the channels are bidirectional and open-drain, no direction-control signal is required, which is essential for the acknowledge-clock-stretching behavior of I2C and DDC. Typical applications are HDMI source, sink, repeater, and switch designs where DDC and CEC lines must be buffered between the HDMI connector and an HDMI processor, EDID EEPROM access circuits, set-top boxes, TVs, AV receivers, and projectors. The buffered DDC prevents a hot-plugged HDMI cable's cable capacitance from corrupting EDID reads, while CEC buffering preserves the single-wire control channel integrity. A key design consideration: connect the EN pin to VCC(B) if the buffer should be always active, and remember that re-enabling introduces a recovery delay, so power sequencing of the two supply pins matters in hot-plug HDMI systems. This page synthesizes distributor pricing tiers, drop-in alternative options, and practical HDMI DDC design notes that are not consolidated in the manufacturer datasheet.
PCA9535RGER - 16-Bit I2C/SMBus I/O Expander, 400kHz | TI
The Texas Instruments PCA9535RGER is a 16-bit, I2C/SMBus-compatible GPIO expander that provides 16 general-purpose input/output lines through a two-wire serial interface. Housed in a 24-pin VQFN (RGE) package with exposed thermal pad, the device operates from a 2.3 V to 5.5 V VCC rail and supports clock frequencies up to 400 kHz (Fast Mode). It includes an interrupt output (INT) that signals the host controller when any input state changes, plus separate input and output configuration registers that allow each I/O to be set independently as input or output. An I/O expander is a category of interface IC designed to add GPIO lines to a microcontroller when its native pin count is exhausted. The PCA9535 belongs to the I/O expander family, which is itself a sub-category of interface ICs and ultimately of the broader digital semiconductor hierarchy. By using only two MCU pins (SCL and SDA), the PCA9535 adds 16 additional GPIOs that behave like native port pins, making it indispensable in space-constrained designs. Key features include 5 V tolerant I/O, 25 mA typical sink capability per output (allowing direct LED drive), latched inputs that eliminate spurious interrupts, and a hardware address pin that supports up to eight devices on the same I2C bus (128 total I/Os). The interrupt is cleared by reading the input port register, simplifying firmware. An internal power-on reset initializes all registers to known states. The architecture uses CMOS logic with low standby current consumption, supporting always-on applications. Internal pull-up resistors are not included on the I/O pins, so external resistors are typically required; SCL and SDA must be pulled high externally per I2C bus specification. Typical applications include server backplane management, industrial PLCs and IO-Link modules, gaming consoles, HVAC control boards, and any embedded system requiring extra buttons, LEDs, or relay drivers. The wide voltage range supports both 3.3 V and 5 V MCUs. When designing, ensure SCL/SDA pull-ups are sized correctly for bus capacitance. Multiple PCA9535 devices can share the bus by using different slave addresses (A0/A1/A2). Consider the INT pin behavior - it is active-low and requires a pull-up. This page consolidates distributor pricing, drop-in cross-brand equivalents (NXP PCA9535, onsemi CAT9555), and practical PCB layout notes not always covered in the manufacturer datasheet.
PCA9539PW/Q900,118 - 16-Bit I2C GPIO Expander | NXP
The NXP PCA9539PW/Q900,118 is a 16-bit I2C-bus/SMBus GPIO expander with interrupt output and active-LOW reset, delivering 16 general-purpose I/O lines over a 400 kHz I2C interface in a 24-pin TSSOP (SOT361-1) package. An I/O expander is an interface IC that adds general-purpose input/output pins to a microcontroller or host processor through a serial bus such as I2C or SMBus. In the system hierarchy, it sits between the host MCU and peripheral circuitry - a power-management and interface component that relieves pin-constrained controllers of the burden of driving buttons, LEDs, switches, and sensors directly. Key features include 16 quasi-bidirectional GPIOs with 5 V tolerant I/Os, a polarity inversion register, an active-LOW open-drain interrupt output, and an external RESET pin that restores the default state without a bus power cycle. The /Q900 variant is qualified to AEC-Q100 for automotive applications and operates from 3.0 V to 5.5 V, versus 2.3 V to 5.5 V for the standard PCA9539PW. Architecturally, the PCA9539 is a CMOS slave device with four register pairs (input, output, polarity inversion, configuration) addressed via two hardware address pins A0 and A1, allowing four devices on one bus for up to 64 I/Os. Configuration registers set each pin as input (high-impedance) or output. The interrupt function flags any input state change for fast host polling, avoiding continuous bus reads. Typical applications include automotive body electronics (door modules, lighting control), keypad and switch scanning, LED drive expansion, server backplane monitoring, and industrial PLC I/O cards where MCU pin count is scarce. Design consideration: unused inputs should not be left floating; tie them to a defined level via the internal or external pull-up, and keep the I2C pull-up resistance sized for the 400 kHz bus load capacitance. This page synthesizes distributor pricing, drop-in alternatives from TI, Nexperia, and NXP standard-grade lines, plus design notes not found in the manufacturer datasheet.
PCA9541APW/01 - 2-to-1 I2C Master Selector, 16-TSSOP | NXP
The NXP PCA9541APW/01 is a 2-to-1 I2C-bus master selector with interrupt logic and reset, designed for high-reliability dual-master I2C-bus applications where system operation must continue even when one master fails or the controller card is removed for maintenance. It is housed in a 16-pin TSSOP (SOT403-1) package and supports 2 masters sharing a single downstream I2C bus, with channel 0 pre-selected at startup per the /01 variant. A 2-to-1 I2C master selector belongs to the broader family of I2C switches and multiplexers, which are themselves a subcategory of serial interface ICs used for digital inter-chip communication. The PCA9541APW/01 specifically enables bus-arbiter functionality by routing one of two upstream master controllers (e.g., a primary and a redundant back-up) onto a single downstream I2C bus segment. It sits between the master controllers and downstream peripherals, providing arbitration, fault isolation, and hot-swap capability. Key features include two upstream I2C channels (SCL0/SDA0 and SCL1/SDA1), one downstream I2C channel (SCL/SDA), an active-low RESET input, hardware-selectable channel at power-up via a startup mode pin, and bidirectional interrupt logic with separate INT0 and INT1 outputs that report which master currently controls the bus. The downstream INT_IN pin collects fault information from peripherals and propagates it upstream when enabled. The device operates from a supply voltage compatible with common 2.3V-5.5V rails and supports standard-mode and fast-mode I2C signaling. Its low on-resistance pass gates and channel-isolation logic keep bus capacitance low, ensuring clean rise/fall times even with long downstream traces. The PCA9541APW/01 variant pre-selects channel 0 at startup, while the /03 variant leaves no channel selected at startup - selection between /01 and /03 lets system designers tune the power-on behavior. Typical applications include redundant server backplanes with dual master controllers, fault-tolerant telecom equipment, hot-swappable controller cards, and industrial PLC systems where two CPUs arbitrate access to shared I2C peripherals. It is also used in RAID storage controllers and ATCA/AdvancedTCA shelf managers that require seamless master failover. When designing with this part, ensure pull-up resistors are present on the active upstream channel and the downstream bus, and follow the standard I2C impedance guidelines because the pass gates do not include internal pull-ups. Decoupling of VCC with a 100nF ceramic capacitor close to pin 16 is recommended. This page synthesizes verified distributor pricing, drop-in alternatives, and practical design notes that complement the manufacturer datasheet.
PCA9541APW/03112 - 2-to-1 I²C Master Selector w/ Interrupt | NXP
The NXP PCA9541APW/03,112 is a 2-to-1 I²C-bus master selector with interrupt logic and reset, housed in a 16-pin TSSOP (PW) package. It operates from a supply voltage of 2.3 V to 5.5 V and provides bidirectional switching between two upstream I²C masters and a single downstream I²C bus, allowing either controller to access shared target devices such as EEPROMs, sensors, and ADCs. What is an I²C master selector? An I²C master selector is a type of bus switch that routes a single shared I²C bus between two (or more) upstream controllers. It sits in the I²C signal chain between the controllers (primary and back-up) and the target devices, behaving like a 1-of-2 multiplexer that is itself controlled by the masters over a separate selection line. Master selectors are commonly used for high-reliability redundant-controller applications where continuous operation must be maintained even when one master fails or is removed for maintenance. In the component taxonomy, the part belongs to: I²C switch -> bus switch -> interface IC -> integrated circuit -> semiconductor. Key features of the PCA9541A family include low standby current, integrated interrupt logic, hardware reset input, and wide 2.3 V to 5.5 V supply compatibility that covers both 3.3 V and 5 V rails. The device supports I²C and SMBus operations and provides bus recovery capability, which is critical when one master becomes unresponsive or the I²C bus is stuck low. Two upstream buses (BUS0, BUS1) connect through the selector to a single downstream bus (BUSX), and an external pull-up resistor pulls the open-drain SDAn/SCLn lines high on each side. The PCA9541APW/03,112 architecture centers on a 1-of-2 bidirectional switch realized with pass-gate MOSFETs and an I²C-compatible control interface. Two address-select pins (A0, A1) allow up to four PCA9541A devices to coexist on the same SMBus, enabling a 1-of-4 or 1-of-8 master selection tree. The reset input (/RESET) restores the selector to a defined default state on power-up or when the active-low signal is asserted by a system supervisor. Typical applications include redundant server management on baseboard management controllers (BMCs), telecom equipment with hot-swappable controller cards, fault-tolerant industrial PLCs, and any dual-master I²C architecture where the controller or a daughter card can be removed without disrupting downstream I²C target devices. Designers also use the part to bridge two electrically isolated I²C domains through a controlled switch. When designing with this device, note that both upstream buses require their own pull-up resistors to the selected supply, and the interrupt output is open-drain and must be pulled high at the system-controller side.
PCA9546AD - 4-Ch I2C Switch with Reset, SOIC-16 | NXP
The NXP Semiconductors PCA9546AD is a quad bidirectional translating I2C-bus and SMBus switch with reset function, housed in a 16-pin SOIC (SO16) surface-mount package. It operates from a 2.3V to 5.5V supply, supports bus speeds up to 400 kHz, and fans out one SCL/SDA upstream pair to four downstream SCn/SDn channel pairs selected via a programmable control register. An I2C switch (also called an I2C multiplexer or I2C bus expander) is an interface IC that sits between a master controller and multiple I2C slave buses. It belongs to the broader hierarchy of I2C bus hub devices within the interface IC family, resolving address conflicts and allowing one controller to manage more devices than a single bus can address, while also isolating capacitive loading per segment. Key features of the PCA9546AD include an active-LOW RESET input that recovers the switch to its default state (all channels deselected) if the I2C bus hangs, four selectable or simultaneously selectable channels determined by the writable control register, and pass-gate translation architecture that allows 1.65V-to-5.5V logic-level translation between low-voltage masters and higher-voltage slaves. The pass-gate switch topology keeps the downstream channel capacitance isolated from the upstream bus until a channel is enabled, reducing total bus capacitance and improving rise times. The control register powers up in a known default state, and the RESET pin allows the system master to recover from bus lockup conditions caused by a slave holding SDA low. Typical applications include multiplexing I2C sensors in industrial automation, expanding address space in server and storage backplanes, connecting multiple camera or display modules in consumer electronics, and isolating fault-prone slave segments in automotive body-electronics networks. A critical design consideration: with any channel enabled, the pass-gate series resistance adds to the bus, so keep pull-up resistor values low enough to meet rise-time requirements at 400 kHz, especially with multiple channels enabled simultaneously. This page synthesizes distributor sourcing data, drop-in alternatives including the Texas Instruments PCA9546A equivalent, and practical design notes not found in the manufacturer datasheet. Per the NXP product page, the PCA9546AD is marked End of Life, so lifecycle planning and second-source qualification are strongly recommended.
PCA9546AD,118 - 4-Ch I2C Bus Switch Reset | NXP | SOIC-16
The NXP PCA9546AD,118 is a 4-channel bidirectional I2C-bus and SMBus translating switch with active-LOW reset, operating from 2.3 V to 5.5 V supply in a 16-pin SOIC (0.154 in, 3.90 mm width) package. A single SCL/SDA upstream pair fans out to four downstream SCx/SDx channel pairs, selectable individually or in any combination via the programmable control register. An I2C multiplexer (bus switch) is an interface IC that solves address-conflict and bus-capacitance problems in I2C systems. In the interface IC hierarchy (I2C switch -> bus multiplexer -> I2C controller peripheral -> interface IC), it sits between a master controller and multiple I2C slave buses, allowing the master to isolate or connect downstream segments on demand. Multiplexing also lets two devices sharing the same slave address coexist on separate channels. Key features include four bidirectional translating switch channels, I2C and SMBus compatibility, three hardware address pins (A0, A1, A2) allowing up to eight PCA9546A devices on one bus, and an active-LOW RESET input that recovers the switch to the all-channels-deselected state if the bus hangs. On power-up all channels are deselected, guaranteeing a deterministic bus state. Low on-resistance pass-gate switches preserve signal integrity for standard-mode and fast-mode I2C traffic. Architecturally, the PCA9546A uses a write-only control register addressed at one of eight I2C addresses set by the A0-A2 pins; the register byte directly maps bits D0-D3 to channels 0-3. Because the pass-gate switches are bidirectional and voltage-translating, upstream and downstream segments may run at different logic levels within the 2.3-5.5 V supply envelope. Maximum power dissipation is rated at 400 mW. Typical applications include multiple sensor or EEPROM buses in industrial automation, camera and display module selection in consumer electronics, and isolating slow or fault-prone slave devices from a shared system management bus (SMBus/PMBus topologies). Design consideration: place the RESET pin pull-up close to the device and use 1-10 kOhm pull-ups on SDA/SCL per bus segment; note that the control register is write-only and the RESET input is the only hardware recovery path. This page synthesizes distributor pricing, drop-in alternatives, pinout detail, and practical design notes not consolidated in the manufacturer datasheet. Note: the NXP product page lists PCA9546AD as End of Life (EOL); plan second-source qualification accordingly.
PCA9548APW - 8-Channel I2C-Bus Switch with Reset | NXP Semiconductors
The NXP Semiconductors PCA9548APW is an 8-channel bidirectional translating I2C-bus switch with reset, controlled via the standard I2C/SMBus interface. The SCL/SDA upstream pair fans out to eight downstream SCx/SDx channel pairs, and any individual channel or combination of channels can be selected via the programmable control register. An active-low RESET input allows the device to recover from a bus-stuck condition, a critical feature in multi-master or hot-swap systems. The device is housed in a 24-pin TSSOP (PW) package rated for -40C to +85C operation. An I2C-bus switch (or multiplexer) is a type of interface IC that sits between a single upstream I2C controller and multiple downstream I2C peripherals, allowing one controller to communicate with several devices that share the same fixed I2C address. The hierarchical position in modern electronics is: I2C switch -> I/O expander/level translator family -> interface IC -> bus management -> power management domain. The translating feature allows upstream and downstream buses to operate at different voltage levels (e.g., 3.3V host with 1.8V or 5V peripherals), eliminating the need for external level shifters. Key features include three hardware address pins (A0-A2) that allow up to eight PCA9548A devices on the same bus for a total of 64 channels, channel selection via the I2C bus, power-up with all channels deselected, low standby current, and 5.5V tolerant I/O. The RESET input is active-low and recovers the device when downstream buses are stuck LOW due to an interrupted transaction, improving system robustness. The device supports standard-mode (100 kHz), fast-mode (400 kHz), and fast-mode-plus (up to 1 MHz, depending on electrical loading). Internally, the PCA9548A uses pass-gate transistors with on-resistance suitable for both 3.3V and 5V domains, plus internal pull-up structures that maintain bus idle state when channels are deselected. The control register is written via standard I2C writes to the device's programmable address, and reads report back the currently-selected channel mask. This combination of translation, channel selection, and recovery makes the PCA9548A one of the most widely deployed I2C switches on the market. Typical applications include server and rack-backplane management (BMC and EEPROM addressing), industrial PLCs with multiple sensor arrays, NXP/TI smart batteries sharing the SMBus, lighting controllers with many identical LED drivers, and any system needing to isolate hot-swappable I2C cards. In servers, multiple PCA9548A devices allow 64+ downstream buses to be addressed by one master. Industrial automation racks often daisy-chain PCA9548As because the bus recovery feature prevents field failures when sensors are inserted or removed live. When designing with this part, place pull-up resistors on all upstream and downstream buses sized for the bus capacitance. Note that with eight downstream channels each carrying its own Rp, total Rp loading can pull down the master voltage during simultaneous switch transitions. Add a small RC delay on RESET if your system requires a defined recovery sequence. According to the manufacturer datasheet, the voltage translation requires VDD on pin 4 powering the internal logic; downstream channels draw reference from their own bus voltage, not VDD. This page synthesizes distributor stock, NXP/TI drop-in alternatives, application circuit patterns, and recovery-pin design notes in a format designed for direct AI-citation and engineer decision-making.