Interface ICs
Subcategories
Products (3,400+)
PCA9555PWR - 16-Bit I2C GPIO Expander | NXP Semiconductors (Tape & Reel)
The NXP Semiconductors PCA9555PWR is a 24-pin CMOS I/O expander with 16 general-purpose parallel input/output ports for I2C-bus and SMBus systems, operating from 2.3 V to 5.5 V in a 24-pin TSSOP package. It adds 16 GPIO lines while minimizing interconnections, supports I2C/SMBus communication at up to 400 kHz according to the distributor listing, and includes interrupt capability for change detection. A GPIO expander is an interface IC that increases the number of digital input and output pins available to a host processor. The PCA9555 belongs to the I2C I/O-expander class, within interface ICs and the broader embedded-control semiconductor hierarchy. Each port bit can be configured independently for input or output, allowing control of LEDs, relays, logic levels, key inputs, and other digital peripherals through the serial bus instead of dedicating host-controller pins. The supplied product information identifies the device as a 16-bit I2C-bus/SMBus GPIO expander with interrupt support. Nexperia’s product information for the same PCA9555PWR family specifies a wide 2.3 V to 5.5 V operating range and default GPIO pull-up resistors. The verified distributor results identify NXP’s PCA9555PWR as an I/O expander in a 24-TSSOP package, while the UMW listing presents the same MPN as a 1 MHz I2C/SMBus variant; that listing is retained as market evidence but is not used to overwrite the target manufacturer specification. The device is useful when a controller has insufficient GPIO resources, especially in industrial controllers, embedded systems, sensors, and compact automation products. The serial interface reduces wiring complexity, while the interrupt output allows a host to respond to input changes without continuously polling the bus. GPIO electrical limits, address options, and detailed timing values were not supplied in the verified data and must be confirmed in the manufacturer datasheet before final design release. For robust PCB implementation, preserve the package footprint and pin numbering, confirm the intended I2C address, route the interrupt line away from fast switching nodes, and validate pull-up resistor values against the bus voltage and capacitance. Do not treat a distributor listing as a substitute for the NXP datasheet when selecting address strapping, power sequencing, or input thresholds.
PCA9557D - 8-Bit I2C/SMBus I/O Expander with Reset | TI (Tape & Reel)
The Texas Instruments PCA9557D is an 8-bit I2C/SMBus I/O expander with configuration registers and a hardware reset input, operating from a 2.3 V to 5.5 V supply and packaged in a 16-pin SOIC (DR) footprint. The device provides general-purpose remote I/O expansion through the two-line bidirectional I2C bus (SCL and SDA) at speeds up to 400 kHz (Fast Mode). Each of the eight I/O pins can be independently configured as either an input or output, and the on-chip register set lets a host microcontroller read pin state and drive output latches over the same two-wire serial link. An I/O expander is a type of digital interface IC that sits on an I2C/SMBus and exposes additional GPIO to a host processor that has too few pins for its application. It belongs to the broader family of parallel-port expanders and, hierarchically, to peripheral ICs > interface ICs > digital logic ICs. Compared to a discrete shift-register approach, an I2C expander uses fewer host pins (only SCL and SDA), supports multi-drop addressing on the bus, and consumes very low standby current. Key features of the PCA9557D include 1 uA maximum standby current, 5 V tolerant I/O, hardware reset via the RESET pin, software reset through the I2C general-call address, and individually configurable I/O direction. The device supports up to eight slave addresses set by A0-A2 (within the PCA9557 family address space) so multiple expanders can share a single bus. An interrupt output (INT) signals the host when any input changes state, avoiding polling overhead. The PCA9557D uses a CMOS process with internal power-on reset and a low-impedance output structure capable of sourcing/sinking 10 mA per bit at 5 V, enabling direct LED drive in many cases. SMBus-alert and hardware-pin reset combine for robust multi-device control. According to the TI PCA9557 datasheet (SCPS155D-family), the device is pin-compatible with the PCA9554/PCA9534/PCF8574 series in 16-pin SOIC. Typical applications include server chassis management, industrial control panels, portable instrumentation, ACPI GPIO expansion on motherboards, keypad scanning, and LED driving on plug-in cards. Designers choose it when they need to expand a microcontroller's GPIO count over I2C while maintaining low standby power. When designing with this device, always include pull-up resistors on SCL, SDA, RESET, and INT per the I2C/SMBus specification (typically 2.2 k to 10 k depending on bus capacitance and speed). Decouple VCC with a 0.1 uF ceramic capacitor placed within 5 mm of the supply pin to suppress switching transients. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving buyers a one-stop comparison source.
PCA9557DB - 8-Bit I2C I/O Expander | Texas Instruments
Texas Instruments PCA9557DB is an 8-bit I2C/SMBus low-power I/O expander with a 2.3 V to 5.5 V operating range, 400 kHz bus speed, and a 16-pin SSOP package. It provides eight remotely controlled general-purpose I/O lines and includes dedicated reset and configuration registers. The device is designed to extend the number of available digital inputs and outputs for embedded systems without requiring a parallel GPIO port on the host controller. An I/O expander is a type of interface IC that connects a serial bus to additional digital lines. The PCA9557DB belongs to the I2C/SMBus GPIO expander family, combining a serial interface controller, configuration registers, and eight quasi-bidirectional I/O ports. Its I2C and SMBus compatibility places it within the broader interface-IC and embedded-control hierarchy, where it can reduce the GPIO requirements of a microcontroller or processor. The PCA9557DB supports a 2.3 V to 5.5 V supply range, allowing use with both 3.3 V and 5 V systems. Its serial interface operates up to 400 kHz, while eight I/O pins provide flexible control of LEDs, logic inputs, or external interface signals. Dedicated configuration registers allow software to identify input or output direction, while the reset and configuration registers support deterministic peripheral initialization and bus management. The device communicates through serial clock and serial data lines, with address selection provided by hardware pins. The SSOP package is a compact surface-mount option, and the verified distributor information identifies the DB ordering variant as a 16-pin SSOP measuring approximately 0.209 inches, or 5.30 mm, in width. Because this is a general-purpose interface device rather than a power semiconductor, a safe operating area chart is not applicable. Typical uses include low-power MCU systems, industrial control modules, sensor-hub boards, LED indicators, and small embedded platforms requiring eight additional digital lines. The PCA9557DB is particularly useful when conserving controller pins is more important than high-speed parallel GPIO operation. Because the serial interface is shared with other bus devices, address configuration, pull-up requirements, and software initialization must be coordinated during board design. Designers should confirm the exact pin functions and electrical limits in the manufacturer datasheet before layout. Bus pull-ups, input thresholds, power sequencing, and the states of I/O pins during reset require careful review. Software should configure each port direction and initial output value before enabling the associated external circuitry to prevent unintended switching. This page consolidates verified manufacturer and distributor information, documents missing electrical parameters transparently, and identifies only same-package drop-in candidates supported by the supplied cross-reference evidence. It also adds application guidance and engineering checks that are not available from a distributor listing alone.
PCA9557DBR - 8-Bit I2C I/O Expander | Texas Instruments
Texas Instruments PCA9557DBR is an 8-bit I2C and SMBus low-power I/O expander with reset and configuration registers, operating from 2.3 V to 5.5 V in a 16-pin SSOP package. It adds eight configurable digital I/O lines to a host controller while using only an I2C or SMBus interface for communication. The manufacturer describes the device as a remote expansion solution for systems whose external parallel I/O requirements exceed the available pins of the main controller. An I/O expander is an interface IC that extends the number of digital input or output lines available to a processor, microcontroller, or other bus master. Its place in the hardware hierarchy is I/O expander → interface controller → interface IC → semiconductor. The PCA9557DBR combines this bus interface with an 8-bit parallel port, making it useful for reducing package size, simplifying control wiring, and adding peripheral connections without requiring a larger host controller. Key features include eight remotely controlled I/O lines, a two-wire I2C/SMBus-compatible interface with a stated bus speed of 400 kHz, and dedicated reset and configuration registers. According to the Texas Instruments product page, the device supports 2.3 V to 5.5 V VCC operation. These characteristics allow the same expander to be used in low-voltage embedded systems as well as conventional 5 V industrial, consumer, and communications equipment without changing the interface arrangement. The device operates as a bus-addressed peripheral, with address and port behavior established through its configuration functions. Because its eight ports are controlled through a serial bus, software can read or change external logic levels without dedicating eight host GPIO pins. The reset function provides a defined initialization route for the expansion logic, while the configuration register supports controlled setup of the I/O behavior. Exact register addresses, polarity settings, and electrical limits should be confirmed in the manufacturer datasheet before firmware or PCB release. Typical uses include low-pin-count embedded controllers, industrial control modules, sensor and actuator interfaces, LED or switch input expansion, and communication equipment needing additional discrete digital lines. The PCA9557DBR is particularly useful where a design must retain a compact host package while adding an eight-bit parallel interface. Because the peripheral communicates over I2C or SMBus, it also avoids the larger routing burden associated with another direct host-to-I/O connection. When laying out a board, place the device close to the connector or controlled circuitry it serves, keep I2C routing short, and provide the required pull-up resistors on SCL and SDA. Account for the device address when multiple expanders share a bus, and use the reset input for a deterministic hardware startup path. Verify bus capacitance, pull-up resistance, voltage compatibility, and logic-level thresholds against the final system conditions. This page consolidates the verified manufacturer description, distributor availability and pricing references, package details, and practical implementation guidance. It also distinguishes confirmed replacement information from parameters that still require datasheet-level verification, helping engineers evaluate the PCA9557DBR without confusing electrically similar devices with verified drop-in choices.
PCA9557DGVR - 8-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCA9557DGVR is an 8-bit I2C and SMBus low-power I/O expander with reset and configuration registers, operating from 2.3 V to 5.5 V and supporting bus speeds up to 400 kHz. It is packaged in a 16-pin TVSOP and provides eight configurable quasi-bidirectional I/O lines through a two-wire serial interface. An I/O expander extends the number of digital input and output pins available to a host controller without adding a dedicated parallel-port bus. The I2C interface carries commands and data over two shared wires, while SMBus compatibility supports common embedded control architectures. This places the PCA9557 within the hierarchy of interface IC, bus expander, GPIO controller, and power-management-aware embedded peripheral. The PCA9557 combines eight independently configurable I/O ports, an active-low reset input, and dedicated configuration registers. Its low standby-current capability, rated at 1 µA maximum in the manufacturer datasheet, makes it suitable for systems that spend significant time in a reduced-power state. The 2.3 V to 5.5 V operating range covers common low-voltage logic systems and 5 V peripheral boards. The active-low RESET input allows a system controller to restore the power-on register state and initialize the I2C or SMBus state machine without removing power from the device. Configuration registers provide centralized control of the port behavior, while the eight ports can be individually programmed for input or output operation. The 400 kHz bus capability provides a practical balance between transfer throughput, wiring simplicity, and low system complexity. Typical uses include industrial control panels, programmable LED indicators, key scanners, sensor and relay interfaces, and compact embedded control boards. The PCA9557 is especially useful when the primary microcontroller or application processor has too few GPIO pins for switches, indicators, interlocks, or remote digital I/O. Design the PCB with short I2C traces, pull-up resistors on SDA and SCL, and a deliberate address assignment through the A0, A1, and A2 pins. Account for the active-low reset signal, validate output drive current for each connected load, and keep bus capacitance and voltage rise time within the limits stated in the manufacturer datasheet. This page combines the manufacturer's functional description, exact ordering information, package details, interface characteristics, and application-oriented engineering guidance. It also distinguishes verified drop-in alternatives from devices that require footprint or function review, helping engineers shorten sourcing and design-in work.
PCA9557DR - 8-Bit I2C/SMBus I/O Expander with Reset | TI
The Texas Instruments PCA9557DR is an 8-bit I2C/SMBus I/O expander with configuration registers and a hardware reset input, operating from a 2.3 V to 5.5 V supply and packaged in a 16-pin SOIC (DR) footprint. The device provides general-purpose remote I/O expansion through the two-line bidirectional I2C bus (SCL and SDA) at speeds up to 400 kHz (Fast Mode). Each of the eight I/O pins can be independently configured as either an input or output, and the on-chip register set lets a host microcontroller read pin state and drive output latches over the same two-wire serial link. An I/O expander is a type of digital interface IC that sits on an I2C/SMBus and exposes additional GPIO to a host processor that has too few pins for its application. It belongs to the broader family of parallel-port expanders and, hierarchically, to peripheral ICs > interface ICs > digital logic ICs. Compared to a discrete shift-register approach, an I2C expander uses fewer host pins (only SCL and SDA), supports multi-drop addressing on the bus, and consumes very low standby current. Key features of the PCA9557DR include 1 uA maximum standby current, 5 V tolerant I/O, hardware reset via the RESET pin, software reset through the I2C general-call address, and individually configurable I/O direction. The device supports up to eight slave addresses set by A0-A2 (within the PCA9557 family address space) so multiple expanders can share a single bus. An interrupt output (INT) signals the host when any input changes state, avoiding polling overhead. The PCA9557DR uses a CMOS process with internal power-on reset and a low-impedance output structure capable of sourcing/sinking 10 mA per bit at 5 V, enabling direct LED drive in many cases. SMBus-alert and hardware-pin reset combine for robust multi-device control. According to the TI PCA9557 datasheet (SCPS155D-family), the device is pin-compatible with the PCA9554/PCA9534/PCF8574 series in 16-pin SOIC. Typical applications include server chassis management, industrial control panels, portable instrumentation, ACPI GPIO expansion on motherboards, keypad scanning, and LED driving on plug-in cards. Designers choose it when they need to expand a microcontroller's GPIO count over I2C while maintaining low standby power. When designing with this device, always include pull-up resistors on SCL, SDA, RESET, and INT per the I2C/SMBus specification (typically 2.2 k to 10 k depending on bus capacitance and speed). Decouple VCC with a 0.1 uF ceramic capacitor placed within 5 mm of the supply pin to suppress switching transients. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving buyers a one-stop comparison source.
PCA9557DT - 8-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCA9557DT is an 8-bit I2C and SMBus low-power I/O expander with reset and configuration registers, a 2.3 V to 5.5 V operating supply range, and a maximum bus clock frequency of 400 kHz. It is packaged as a 16-pin SOIC in the DT ordering configuration. The device expands one serial I2C interface into eight configurable parallel I/O lines, reducing microcontroller pin count and simplifying control of external digital functions. An I/O expander is an interface IC that translates serial commands from an I2C or SMBus controller into parallel digital inputs or outputs. The PCA9557 belongs to the broader embedded-interface hierarchy: I/O expander -> bus interface device -> interface IC -> semiconductor. It is useful when a system needs additional control or status lines without increasing the pin count of the main microcontroller, embedded processor, or programmable logic device. Key features include eight I/O ports, reset and configuration registers, support for both input and output operation, and low standby current consumption of 1 uA maximum according to the manufacturer data. The verified distributor listing identifies a 400 kHz I2C/SMBus interface and a 16-SOIC package. The PCA9557DT is intended for designs requiring a compact, serial-to-parallel expansion function, although exact pin names, electrical limits, and register behavior should be confirmed in the manufacturer datasheet before layout or firmware implementation. The device is used as an I2C target and communicates with a host controller through addressable registers. A host can configure port direction and then read or write port state, subject to the register definitions and electrical limits in the datasheet. Because I2C bus capacitance, pull-up resistance, address configuration, and peripheral power sequencing affect reliability, the device should be placed with short traces away from noisy switching stages. Typical applications include industrial control modules, sensor and actuator interfaces, programmable digital I/O, instrumentation, embedded control boards, and systems that need eight additional lines without expanding the host controller. The device can also complement a microcontroller such as an STM32H750VBT6TR when its direct GPIO budget is reserved for higher-speed or interrupt-sensitive functions. When selecting a replacement, verify the SOIC-16 footprint, pin mapping, I2C address behavior, reset requirements, output-drive limits, supply range, and register compatibility. PCA9557D is a relevant same-family ordering option, but package suffix and availability must be checked against the manufacturer’s ordering information. This page consolidates manufacturer and distributor sources, identifies the verified operating envelope, and provides practical design guidance for I2C bus design, decoupling, pull-ups, and lifecycle planning. It is intended to support component selection before the complete manufacturer datasheet is used for final electrical and production qualification.
PCA9557PW - 8-Bit I2C I/O Expander | NXP | 16-TSSOP
The NXP Semiconductors PCA9557PW is an 8-bit I2C/SMBus parallel input/output expander operating from 2.3 V to 5.5 V, with a 400 kHz bus rate and a 16-pin TSSOP package. It combines an 8-bit input port register, an 8-bit output port register, and an I2C/SMBus interface, allowing a microcontroller to control or monitor eight additional digital lines. The device also provides low current consumption and a high-impedance open-drain output on IO0. An I/O expander is an interface IC that extends the number of general-purpose inputs and outputs available to a host processor. The PCA9557 belongs to the parallel I/O expander class, connects to the I2C/SMBus hierarchy, and reduces the number of host-controller pins needed for buttons, indicators, relays, logic controls, and other digital peripherals. Its operating voltage range supports both 3.3 V and 5 V system contexts where the host and external signals use compatible logic levels. The verified product information identifies an 8-bit I/O expander, a 400 kHz I2C/SMBus interface, a 2.3 V to 5.5 V VCC range, and a 16-TSSOP package. The controller can configure the port direction and access the input and output registers through the serial bus. IO0 is specifically described as a high-impedance open-drain output, while the remaining port behavior and electrical limits should be confirmed in the manufacturer datasheet before final design release. Typical applications include low-pin-count embedded control, keypad and switch input consolidation, LED or indicator control, relay-interface logic, sensor-gate control, and general industrial or consumer equipment requiring eight remote digital lines. The I2C interface makes the PCA9557 especially useful when the host has limited spare pins but can provide an I2C bus. Firmware must define the device address, register behavior, port direction, pull-up requirements, and any open-drain load arrangement. For PCB implementation, place the device close to the connector or controlled signal group, route SDA and SCL as a short bus pair, and provide pull-up resistors only after checking the bus voltage, capacitance, speed, and number of devices. Do not assume that a mechanically similar 16-TSSOP part is pin-compatible: compare address, register map, pin functions, electrical limits, and I/O behavior against the manufacturer datasheet. This page consolidates the verified NXP product identity, package and bus information, practical application context, and the need for datasheet-level validation. It distinguishes confirmed facts from parameters that require a specific datasheet revision or device variant before being used in a production design.
PCA9557PWR - 8-Bit I2C I/O Expander | NXP | 16-TSSOP (Tape & Reel)
The NXP Semiconductors PCA9557PWR is an 8-bit I2C/SMBus parallel input/output expander operating from 2.3 V to 5.5 V, with a 400 kHz bus rate and a 16-pin TSSOP package. It combines an 8-bit input port register, an 8-bit output port register, and an I2C/SMBus interface, allowing a microcontroller to control or monitor eight additional digital lines. The device also provides low current consumption and a high-impedance open-drain output on IO0. An I/O expander is an interface IC that extends the number of general-purpose inputs and outputs available to a host processor. The PCA9557 belongs to the parallel I/O expander class, connects to the I2C/SMBus hierarchy, and reduces the number of host-controller pins needed for buttons, indicators, relays, logic controls, and other digital peripherals. Its operating voltage range supports both 3.3 V and 5 V system contexts where the host and external signals use compatible logic levels. The verified product information identifies an 8-bit I/O expander, a 400 kHz I2C/SMBus interface, a 2.3 V to 5.5 V VCC range, and a 16-TSSOP package. The controller can configure the port direction and access the input and output registers through the serial bus. IO0 is specifically described as a high-impedance open-drain output, while the remaining port behavior and electrical limits should be confirmed in the manufacturer datasheet before final design release. Typical applications include low-pin-count embedded control, keypad and switch input consolidation, LED or indicator control, relay-interface logic, sensor-gate control, and general industrial or consumer equipment requiring eight remote digital lines. The I2C interface makes the PCA9557 especially useful when the host has limited spare pins but can provide an I2C bus. Firmware must define the device address, register behavior, port direction, pull-up requirements, and any open-drain load arrangement. For PCB implementation, place the device close to the connector or controlled signal group, route SDA and SCL as a short bus pair, and provide pull-up resistors only after checking the bus voltage, capacitance, speed, and number of devices. Do not assume that a mechanically similar 16-TSSOP part is pin-compatible: compare address, register map, pin functions, electrical limits, and I/O behavior against the manufacturer datasheet. This page consolidates the verified NXP product identity, package and bus information, practical application context, and the need for datasheet-level validation. It distinguishes confirmed facts from parameters that require a specific datasheet revision or device variant before being used in a production design.
PCA9570GMH - 4-Bit I2C GPO Expander | NXP | XQFN-8
NXP PCA9570GMH is a 4-bit general-purpose output expander that adds push-pull digital outputs to a host processor through an I2C-bus interface. It supports bus speeds up to 1 MHz while maintaining backward compatibility with Fast-mode at 400 kHz and Standard-mode at 100 kHz. The device is supplied in an 8-pin XQFN package measuring 1.6 mm by 1.6 mm and includes an exposed thermal pad according to the distributor listing. An I2C output expander is a semiconductor interface device that converts a serial two-wire bus into additional parallel control outputs. In the product hierarchy, the PCA9570GMH belongs to the I/O expander class, within interface ICs and logic ICs. Unlike a general-purpose input/output expander, the PCA9570 is a streamlined GPO device whose four outputs are configured as push-pull drivers. This makes it suitable for controlling loads that require a driven logic level rather than a high-impedance input. Key features include four general-purpose parallel outputs, 1 MHz I2C-bus operation, and compatibility with both 100 kHz and 400 kHz bus standards. The low-voltage CMOS construction targets processor-based and handheld battery-powered equipment. The small XQFN-8 footprint helps reduce board area when a controller has too few output pins for relays, indicators, logic enables, or other digital loads. The PCA9570GMH is a streamlined output-only expander, so its register and pin arrangement should be compared carefully with mixed input/output or bidirectional expanders before substitution. Its four push-pull outputs provide defined high and low states, making the device appropriate for simple control signals in consumer electronics, mobile accessories, battery-powered instruments, and compact embedded systems. In a typical design, the host connects SDA and SCL to the PCA9570GMH, writes the desired output pattern to the device register, and reads back the output states. The bus lines require pull-up resistors in accordance with the I2C specification. Because the package exposes a pad, the PCB layout should maximize copper area under the exposed pad to improve heat spreading. For power-sensitive designs, the quiescent current and output-driver loading should be checked against the system battery budget. Because every host controller needs a reliable I2C pull-up arrangement, verify the bus capacitance, pull-up resistance, and level-shifting requirements before layout release. Use the pin-connection and register details in the manufacturer datasheet when assigning PCB tracks.
PCA9571GUX - 8-Bit 1MHz I2C Output Expander | NXP
NXP Semiconductors PCA9571GUX is an 8-bit general-purpose parallel output expander for low-voltage processor and handheld applications, with I2C communication up to 1 MHz and a 12-pin XQFN package measuring 2 mm by 1.7 mm. The device operates in Standard-mode at 100 kHz, Fast-mode at 400 kHz, and 1 MHz modes on a lightly loaded bus with less than 100 pF capacitance. An I2C output expander is an interface IC that adds parallel digital outputs to a serial bus. The hierarchy runs from I2C output expander to GPIO expander, interface expander, and semiconductor. It is useful when a processor has too few general-purpose output pins to control multiple discrete loads while the system architecture requires a shared serial control bus. The PCA9571GUX provides eight general-purpose parallel outputs and supports 1 MHz I2C operation while retaining backward compatibility with 100 kHz Standard-mode and 400 kHz Fast-mode buses. Backward compatibility allows the same device to operate alongside slower peripherals on a shared bus, although total bus capacitance, pull-up selection, and signal-integrity margin remain system-level constraints. The streamlined output-only architecture distinguishes this device from bidirectional I/O expanders. It does not provide input pins for state readback, so its primary function is command and control rather than monitoring external logic levels. The 2 mm by 1.7 mm XQFN package supports compact designs where board area is important, although the fine-pitch footprint requires careful PCB assembly and inspection. Typical applications include portable-device control, low-voltage processor systems, battery-powered equipment, and systems that need multiple parallel outputs driven over I2C. Product family members can be useful in portable and mobile equipment, industrial controllers, embedded systems, and peripheral-control designs where eight outputs reduce the number of direct host-controller connections. Designers should confirm the address configuration, output behavior, voltage limits, and pin mapping in the manufacturer datasheet before finalizing a PCB. The 1 MHz operating rate is intended for a lightly loaded bus below 100 pF; pull-up resistance, cable length, peripheral capacitance, and signal rise time must be evaluated together when the bus includes long traces or additional devices. This page organizes the PCA9571GUX function, interface characteristics, package constraints, application guidance, comparison points, and replacement criteria so that engineers can assess the device alongside other I2C output-expansion options before committing a board layout.
PCA9600D,118 - 1 MHz I2C-bus Buffer/ReDriver | NXP | 8-SO
The NXP PCA9600D,118 is a dual bidirectional bus buffer/ReDriver designed to isolate I²C-bus capacitance in point-to-point and multipoint applications up to 4000 pF. Housed in an 8-pin SO (SOIC-8) package, it operates at speeds up to at least 1 MHz and provides a non-latching, bidirectional logic interface between a standard I²C-bus and higher-capacitance or different-voltage bus segments. The high-drive side is compatible with the Fast-mode Plus (Fm+) specification, making the PCA9600 a higher-speed upgrade to the legacy P82B96. What is an I²C bus buffer? An I²C-bus buffer/ReDriver is a dedicated interface IC that sits between two bus segments to overcome the 400 pF capacitive limit of standard I²C. By isolating capacitance, a buffer allows engineers to extend bus length, add more nodes, use lower-cost cabling, or bridge between logic-voltage domains. Buffers/ReDrivers belong to the interface IC hierarchy: interface IC > bus buffer > I²C extender > signal conditioning, and are widely used in industrial backplanes, sensor arrays, and LED lighting chains where long cable runs would otherwise exceed the bus's RC budget. Key features of the PCA9600 include an operating supply voltage range from 2.5 V to 15 V on the low-voltage (standard I²C) side, with logic-level translation capability through the dual-rail architecture. The part is specified for -40 °C to +85 °C operation and offers high-impedance logic pins that prevent bus latching during plug-in or brown-out events. The device is bus-isolating rather than bus-repeating, so it cannot sink the I²C pull-up current from both sides simultaneously—designers must provide pull-ups on each side. Architecturally, the PCA9600 uses an internal pass-FET-style transmission gate with direction-sense amplifiers that detect which side is driving and steer current accordingly without requiring an external direction-control pin. The result is a drop-in, transparent bus extender that does not occupy an I²C address and does not appear as a node. Compared to discrete MOSFET plus pull-up solutions, the PCA9600 guarantees matched thresholds, controlled rise/fall times, and known hot-swap behavior across temperature. Common applications include industrial control backplanes, large-display LED driver chains, remote sensor arrays, and any system where the I²C master sits on one PCB and the slaves are several meters away on a cable or harness. The PCA9600D,118 ships on 13-inch tape and reel and is fully RoHS compliant, targeting high-reliability commercial and industrial designs. When designing with this part, pay close attention to the pull-up placement: each bus segment requires its own pull-up resistor sized for that segment's capacitance and the target rise time. Designers commonly pair the PCA9600 with 4.7 kΩ pull-ups on the master side and 1 kΩ to 2.2 kΩ pull-ups on the high-drive side to handle the larger bus capacitance.
PCA9601D,118 - 1MHz Fm+ I2C Bus Buffer SO-8 | NXP
The NXP PCA9601D,118 is a dual bidirectional I2C-bus buffer and repeater supporting operation to at least 1 MHz (Fast-mode Plus), with a wide 2.5 V to 15 V supply range, up to 4000 pF bus capacitance drive capability, and an 8-pin SO (SOIC-8) surface-mount package. An I2C-bus buffer is a specialized interface IC inserted between a controller-side I2C bus and one or more remote bus segments. Because the standard I2C bus is limited by total capacitance (typically 400 pF) and by the driving strength of the master device, long cables, backplanes, and daughter-card architectures quickly exceed these limits. A buffer isolates the capacitance of each bus segment, regenerates the signal edges, and allows each side to use a different supply voltage, making it a key building block within the interface IC and bus repeater/redriver family. Key features of the PCA9601 include bidirectional, non-latching signal transfer in both directions, compatibility with Fast-mode Plus (Fm+) drive requirements on the high-drive B-side, and voltage-domain separation so a 3.3 V controller bus can drive a 5 V, 12 V, or 15 V remote bus. According to NXP, the part isolates I2C-bus capacitance and permits point-to-point or multipoint buses of up to 4000 pF. Technically, the device implements an open-drain bidirectional buffer using NXP's proprietary level-shifting buffer architecture derived from the P82B96 family. It is a higher-speed version of the P82B96 and a higher-drive version of the PCA9600, meaning more Fm+ targets can hang on remote bus segments without timing violations. The 50 ns propagation delay class and 1 MHz capability keep rise/fall budgets intact at Fm+ speeds. Typical applications include long I2C runs in industrial backplanes, LED display panels, battery management systems, and remote daughter cards carrying many I2C targets where capacitance and drive strength would otherwise limit the bus. Design consideration: place the buffer close to the controller-side connector and size pull-up resistors separately for each bus segment, because the two sides have different drive strengths and voltage levels. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
PCA9601DPZ - 1MHz Dual I2C-Bus Buffer | NXP Semiconductors
The NXP Semiconductors PCA9601DPZ is a dual bidirectional I2C-bus buffer and repeater that isolates bus capacitance and drives loads up to 4000 pF, operating at speeds up to 1 MHz (Fast-mode Plus) in an 8-pin TSSOP surface-mount package. An I2C-bus buffer is a type of interface IC that sits between a standard I2C master/target segment and a long or heavily loaded bus segment. In the interface IC hierarchy (bus buffer -> signal repeater -> interface IC), its role is to regenerate signal edges and isolate capacitance, because the I2C specification limits total bus capacitance and rising-edge time. By splitting one bus into short segments, a buffer allows long cables, backplanes, and daughter-card interconnects that would otherwise violate I2C timing. Key features of the PCA9601 include 4000 pF bus drive capability, non-latching bidirectional logic that preserves the wired-AND I2C arbitration and clock-stretching behavior, and a high-drive side compatible with Fast-mode Plus (Fm+) specifications. It supports level translation between mixed-voltage bus segments (3.3V, 5V, and higher-voltage buffered sides), enabling communication between 3.3V and 5V systems while maintaining signal integrity and timing. The PCA9601 is architecturally a higher-speed version of the well-established P82B96 and a higher-drive version of the PCA9600. Its buffered, non-latching topology means the buffer never locks up during arbitration or repeated starts, a common failure mode of simpler repeater designs. The high drive strength allows many more Fast-mode Plus targets on remote daughter cards than an unbuffered bus could support. Typical applications include point-to-point and multipoint extension of I2C buses across cables and backplanes, isolating capacitance of remote daughter cards, mixed-voltage (3.3V/5V) system interfacing, and industrial or telecom equipment where many Fm+ targets must share a long bus. Devices such as the PCA8574, PCA9539, and PCA9538 I/O expanders are typical loads at the far end of a buffered segment. Design considerations: the PCA9601 specifies an operating temperature range of 0 C to 85 C, so it is intended for commercial and industrial indoor use rather than automotive-grade environments. Verify bus segment capacitance on both sides and follow the datasheet for pull-up sizing on the buffered side to meet Fm+ rise-time requirements. This page synthesizes distributor pricing context, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet, with data verified as of 2026-10-20.
PCA9614DP,118 - 2-Ch Fm+ Differential I2C Bus Buffer | NXP
The NXP PCA9614DP,118 is a 2-channel multipoint Fast-mode Plus (Fm+) differential I2C-bus buffer with 400 kHz buffered operation, dual-supply differential signaling, and a 10-pin TSSOP (DP) surface-mount package. It extends a normal single-ended SMBus/I2C-bus across electrically noisy environments using a differential I2C (dI2C) physical layer that is fully transparent to the SMBus/I2C-bus protocol layer. An I2C-bus buffer and repeater is an interface IC that regenerates and drives bus signals, increasing fan-out, breaking capacitance limits, and lengthening bus reach. Within the interface IC hierarchy, buffer ICs sit between an I2C master/peripheral and the physical wire, and differential buffers such as this one add a robust physical layer without changing the protocol, so standard controllers require no firmware changes. Key features include two independent buffer channels supporting multipoint dI2C links over long cables, an EN pin that places the device in an idle state to stop traffic propagation, and an internal pull-up on EN that holds the device enabled by default. The differential transmission rejects common-mode noise, making the link tolerant of ground potential differences between boards. Technically, the PCA9614 converts the single-ended SDA/SCL levels into a differential pair per channel at the buffer output side, and converts back to single-ended at the receiving end when paired with another differential buffer. Because the dI2C layer is protocol-transparent, arbitration, clock stretching, and Fm+ 400 kHz (1 MHz capable) timing behave exactly as on a standard bus, while cable capacitance and noise immunity requirements are decoupled from the bus segment. Typical applications include industrial automation bus extension, rack and backplane inter-board communication in servers, battery management systems in electrically noisy traction environments, and long-run I2C links between enclosures or display modules. A key design consideration is power sequencing of the dual supplies (VDD(A) on the single-ended side and VDD(B)/VL on the differential side); both must remain within the datasheet recommended operating conditions and EN should be held low during startup to prevent glitching. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, with freshness data as of 2026-10-20.
PCA9615DPZ - 2-Ch I2C Fast-Mode Plus Diff Buffer | NXP
The NXP Semiconductors PCA9615DPZ is a 2-channel multipoint Fast-mode Plus differential I2C-bus buffer with hot-swap logic, operating up to 1 MHz, housed in a 10-pin TSSOP (SOT552-1) package. It supports standard I2C, Fast-mode, and SMBus compatibility, with single-ended I2C on the card side up to 540 pF and differential I2C on the cable side supporting multi-drop bus up to 3 meters. The device uses an external DCEN pin to enable/disable the differential driver and operates from dual supplies, typically VDD(A) on the single-ended side and VDD(B) on the differential side. A signal buffer, repeater, or redriver is an active interface IC placed in-line on a bus to restore signal integrity when the load capacitance or physical distance exceeds the limit of the bus specification. In the I2C hierarchy, this part is a specialized bus extender/repeater that converts a single-ended SDA/SCL pair into a differential pair for transmission over twisted-pair or shielded cable, then converts back at the far end. This is essential in industrial control, automotive sensor backbones, and large backplane systems where standard I2C's capacitive limit (~400 pF) is insufficient. Key features of the PCA9615DPZ include differential transmission across a cable up to 3 meters at Fast-mode Plus speeds, hot-swap logic that allows the card to be inserted into a live backplane without disturbing the bus, wide supply range (2.7 V to 5.5 V on VDD(A) and 3.0 V to 5.5 V on VDD(B)), and AEC-Q100 qualification for automotive applications. The hot-swap circuitry prevents inrush current and bus glitches during card insertion. The differential pair uses low-voltage signaling to reduce EMI compared to single-ended transmission. Typical applications include industrial I2C backplane extension, automotive sensor networks, hot-swappable I/O cards, multi-drop I2C sensor clusters, and remote sensor/PCI configuration. The device is particularly valuable where cables must span meters between cards, sensors, or backplane slots, and where live insertion is needed without disrupting the system bus. When designing with this part, ensure both VDD rails are decoupled with 100 nF ceramic capacitors placed within 5 mm of the supply pins. Verify the differential pair routing on the cable side is twisted-pair or shielded to meet EMI requirements; the part itself does not include cable termination resistors, so external 100 ohm differential termination may be required at the far end for very long runs.
PCA9616PW - 3-Channel Differential I2C Bus Buffer | NXP
The NXP Semiconductors PCA9616PW is a dual-supply, 3-channel multipoint Fast-mode Plus (Fm+) differential I2C-bus buffer with hot-swap logic, packaged in a 16-pin TSSOP (PW) surface-mount package. It buffers the single-ended SMBus/I2C-bus up to 1 MHz and converts it to a differential I2C (dI2C) bus that reliably extends communication through electrically noisy environments over cable runs of at least 3 meters, or longer at reduced clock speeds. A differential I2C-bus buffer, sometimes called a bus repeater or redriver, is an interface IC that belongs to the signal buffer family within the broader hierarchy of interface integrated circuits. Where a plain I2C bus uses open-drain single-ended lines vulnerable to ground bounce and common-mode noise, a dI2C buffer translates the bus into a differential current-mode signaling scheme, dramatically improving common-mode noise immunity while remaining fully compatible with existing Standard-mode, Fast-mode, and Fast-mode Plus I2C and SMBus devices. Key features of the PCA9616PW include its 3-channel multipoint architecture, which supports a dI2C bus shared by multiple nodes for multipoint topologies; its dual-supply design isolating the single-ended side from the differential side; support for Fast-mode Plus operation at 1 MHz; and integrated hot-swap logic that allows a card or module to be inserted into or removed from a live backplane without corrupting bus transactions. Signal direction is fully automatic, requiring no external direction-control signal. Technically, the device pairs each single-ended SDA and SCL line with differential transmit/receive pairs on the cable side, using current-mode differential drivers and receivers with high common-mode noise rejection. Because it is a multipoint buffer, several PCA9616 devices can share one differential cable, enabling distributed systems such as rack-mounted cards, industrial backplanes, and remote sensor clusters. NXP documents cable extension of at least 3 m, with longer runs achievable at lower bus speeds. Typical applications include industrial backplane I2C distribution, telecom and server shelf management, multipoint sensor networks in electrically noisy factory environments, and hot-pluggable module bus extension. The hot-swap logic makes it especially suitable for field-replaceable cards. Design consideration: plan the differential bus topology to respect multipoint stub-length limits, and verify supply sequencing on both the single-ended and differential rails against the manufacturer datasheet to guarantee correct hot-swap behavior. This page synthesizes distributor pricing, drop-in replacement analysis, and practical design notes not found in the manufacturer datasheet.
PCA9618UKZ - Single-Channel Fm+ I2C Bus Repeater | NXP
NXP Semiconductors PCA9618UKZ is a single-channel CMOS repeater for Fast-mode Plus I2C-bus or SMBus signals, with a 4-WLCSP package measuring 0.83 mm by 0.78 mm. It can buffer either the SCL clock line or the SDA data line, and it also supports single-bit buffering applications. An I2C bus repeater is an interface IC that regenerates a digital communication signal between a bus controller and a downstream device. Repeaters extend usable bus distance, isolate capacitive loading, improve signal integrity, and allow separate bus segments to operate at compatible logic levels. In the broader semiconductor hierarchy, the PCA9618UKZ is a bus repeater, then an interface IC, then an integrated circuit and semiconductor. The principal benefit of the PCA9618UKZ is its combination of Fm+ I2C or SMBus compatibility, one-bit architecture, and compact WLCSP-4 footprint. The small package supports placement close to a connector, bus branch, or device interface. Its single-channel format also allows designers to add buffering where required rather than fitting a multi-channel device that would remain unused. The device is intended for separating clock and data paths when capacitive loading, bus extension, or signal-integrity constraints become important. In a typical implementation, the incoming side connects to the host or bus master, while the output side drives a downstream peripheral. The buffered path reduces the electrical loading seen by the source while maintaining the logic signaling required by I2C-compatible devices. Typical uses include sensor networks, industrial controllers, consumer equipment, communications modules, and compact embedded systems that use I2C or SMBus. The device is also suitable for generic single-bit level translation or buffering where the system requires regenerated logic rather than a multi-channel fixed-direction translator. Designers should place the repeater near the branch or load that requires isolation, verify timing margins at the intended bus rate, and account for package parasitics and board-level capacitance. The 4-WLCSP footprint also demands careful PCB layout, stencil and reflow control, and inspection because its ball pitch and dimensions leave little room for rework. This page consolidates the confirmed function, package information, sourcing details, interface considerations, and drop-in replacement status of the PCA9618UKZ. It also distinguishes verified device facts from electrical parameters that engineers must confirm in the NXP product specification before finalizing a design.
PCA9641PWJ - 2-Channel I2C Bus Arbiter | NXP
The NXP Semiconductors PCA9641PWJ is a 2-channel I2C bus controller arbiter and 2-to-1 master demultiplexer packaged in a 16-pin TSSOP. It is designed for dual-controller I2C systems in which two bus masters may issue commands simultaneously. The arbitration function selects one controller as the winner, allows that controller to operate without interruption, and enables the losing controller to take control when arbitration is required. An I2C controller arbiter is a specialized interface IC that manages competing requests to use a shared two-wire bus. The broader hierarchy is I2C controller arbiter, I2C bus interface, interface IC, semiconductor, and electronic component. Unlike a conventional I2C bus switch or channel multiplexer, the PCA9641 is specifically intended to arbitrate between two master controllers while also routing commands through a 2-to-1 master demultiplexer. The manufacturer identifies the PCA9641 as a 2-to-1 I2C master demultiplexer with an integrated arbiter function. Its principal role is high-reliability dual-master operation: the arbiter elects a winning master and prevents simultaneous masters from interfering with one another. The losing master can subsequently assume control of the shared I2C bus when the winning master releases it. This behavior is useful where deterministic bus ownership is needed more than simply routing separate I2C branches. Typical PCA9641PWJ applications include redundant or alternate industrial controllers, dual-processor instrumentation, embedded test equipment, controller isolation in complex electronics, and systems in which two embedded masters share access to the same peripheral bus. The device helps centralize command arbitration close to the I2C domain, reducing the need for firmware-level coordination during simultaneous access attempts. The PCA9641PWJ is identified by NXP as a 16-TSSOP device, and distributor listings classify it as a two-channel buffer and multiplexer. Because arbitration behavior depends on the complete circuit, designers should follow the manufacturer datasheet for pin assignments, electrical limits, operating conditions, timing, and recommended application wiring rather than relying on generic I2C-switch schematics. For PCB implementation, place the device close to the controlled I2C segment, route clock and data traces as a matched pair, and keep the arbitration inputs, master request signals, and bus connections away from noisy switching stages. The 16-pin TSSOP footprint supports compact designs, but power, ground, and signal-integrity requirements should be checked against the latest NXP documentation before layout release. This page organizes the exact product identity, manufacturer documentation, package information, application context, and verified replacement information for PCA9641PWJ. It also distinguishes true drop-in candidates from parts that are only functionally similar, helping engineers assess PCB reuse without assuming that equivalent bus-routing functions guarantee identical pin compatibility.
PCA9670BS,118 - 8-bit Fm+ I2C I/O Expander w/ Reset, HVQFN-16
The NXP PCA9670BS,118 is a remote 8-bit I/O expander for Fast-mode Plus (Fm+) I2C-bus with reset, packaged in a 16-pin HVQFN (3x3 mm) with exposed thermal pad. The device provides general-purpose remote I/O expansion for most microcontroller families via the two-line bidirectional I2C-bus, and supports a clock frequency of up to 1 MHz. Operating supply range is 2.3 V to 5.5 V, allowing use with 3.3 V and 5 V logic rails. The integrated RESET input and quasi-bidirectional I/O structure simplify firmware and PCB design when adding buttons, LEDs, keypads, or sensor interfaces to an embedded system. An I/O expander (also called a port expander or GPIO expander) is a category of interface IC that multiplies the limited GPIO pins of a microcontroller through a serial bus. In the taxonomy I/O expander -> interface IC -> integrated circuit -> semiconductor, the PCA9670BS sits in the parallel-bus-expansion tier and uses I2C as the transport. By attaching the part to SCL/SDA, designers gain eight additional quasi-bidirectional I/O pins addressed through a 7-bit slave address. Three hardware address pins (A0, A1, A2) allow up to 64 PCA9670 devices on the same bus, supporting up to 512 I/Os (for example 512 LEDs) without external bus buffers. Key features include 1 MHz Fm+ bus support (compared with 400 kHz for the classic PCF8574), a hardware RESET pin that reverts all ports to inputs, low standby current, and 5 V tolerant I/O structure that tolerates bus pulls above VDD. The HVQFN-16 (3x3) package provides a low 0.5 mm profile with an exposed die attach paddle for improved thermal performance, making it suitable for compact industrial, consumer, and IoT designs. NXP specifies ESD protection exceeding 2 kV HBM on the I/O pins, and the part is qualified to the industrial -40 C to +85 C operating range. The PCA9670 architecture uses an I2C state machine with interrupt logic for input-change notifications and a separate RESET input that asynchronously clears internal state. Internally each I/O pin is a quasi-bidirectional structure - capable of sinking current to drive LEDs directly while also serving as an input when written high. This dual-mode behavior differs from push-pull GPIO and is important when migrating designs from the older PCF8574/PCF8575 family. Typical applications include keypad and button-matrix scanning in white goods and access control, LED driving and chase patterns in industrial control panels, sensor multiplexing on Raspberry-Pi-class SBCs where the host lacks enough native GPIO, and general-purpose I/O expansion in PLC and HVAC controllers. The wide 2.3-5.5 V supply range plus 1 MHz Fm+ bus speed also suits battery-powered IoT nodes that need to minimize I2C transaction time. When designing with this part, place 100 nF decoupling close to VDD, use external pull-ups on SDA/SCL sized for the bus capacitance (typically 4.7 kohm at 1 MHz), and avoid leaving the RESET pin floating - tie it to VDD through a 10 kohm resistor or drive it from the host MCU. The I/O sink capability must be checked against LED forward current; sourcing current is limited and the quasi-bidirectional behavior must be considered when interfacing to logic-level peripherals. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the NXP datasheet.
PCA9675PW,118 - 16-bit Fm+ I2C I/O Expander | NXP | TSSOP-24
The NXP PCA9675PW,118 is a 16-bit remote I/O expander for the Fast-mode Plus (Fm+) I²C-bus, supplied in a 24-pin TSSOP (PW) package and shipped on 13-inch tape and reel. It operates from a supply voltage of 2.3 V to 5.5 V, clocks the I²C interface at up to 1 MHz, and exposes 16 quasi-bidirectional I/O lines that can source/sink up to 30 mA per pin with a 100 mA total package limit. An I/O expander (also called a port expander or GPIO expander) is a category of interface IC that increases the number of general-purpose I/O pins available to a host microcontroller over a serial bus such as I²C. In the system hierarchy it sits between the MCU and the discrete digital loads (LEDs, keypads, sensors, relay coils), translating compact I²C transactions into parallel pin-level updates. The PCA9675 belongs to NXP's Fm+ family, which is optimized for high-speed serial I/O expansion in noisy or long-trace industrial backplanes. Key features include three hardware address pins (A0/A1/A2) supporting up to eight PCA9675 devices on the same bus, an active-low interrupt output (INT) that asserts when any input changes and releases on the next I²C read, an active-low reset input with internal power-on reset, and per-pin latch-up current exceeding the 100 mA JESD78 limit. The device is a drop-in upgrade for the legacy PCF8575, lifting bus speed from 400 kHz to 1 MHz and raising sink current capability. Typical applications include PWM dimming of LED arrays (each pin can be modulated at >1 MHz bus rates), keypad and switch-matrix scanning, fan-speed and relay control in industrial PLCs, and general-purpose I/O expansion for low-pin-count MCUs in white goods, HVAC, and IoT edge nodes. Designers value the wide 2.3–5.5 V supply range because it allows direct interface to both 3.3 V and 5 V microcontrollers without level shifters. When designing with this device, place 100 nF decoupling on VDD as close as possible to the pin and pull SDA/SCL high with 4.7 kΩ resistors for standard 400 kHz operation or 1 kΩ for the full 1 MHz Fm+ rate. Note that quasi-bidirectional outputs require no external pull-up on the load side because an internal weak pull-up is enabled after each read cycle.
PCA9703PW/Q900 - 16-bit SPI GPI, 18V Tolerant | NXP
The NXP Semiconductors PCA9703PW/Q900,118 is an 18 V tolerant, 16-bit SPI General Purpose Input (GPI) shift register with maskable interrupt output, housed in a 24-pin TSSOP (PW) package rated -40 C to +125 C. It operates as an SPI slave at up to 5 MHz and monitors 16 switch or logic inputs with 18 V input tolerance, making it a low-power solution for high-voltage switch status monitoring in automotive and industrial systems. A GPI (General Purpose Input) shift register is a type of input-only I/O expander within the broader hierarchy of interface ICs -> I/O expanders -> parallel-in serial-out shift registers. Unlike I2C GPIO expanders, SPI GPI shift registers stream input states to a microcontroller as a serial bit field, which minimizes pin count on the host MCU and gives deterministic, fast read-back of many switch contacts. Key features include 16 input-only channels tolerant to 18 V regardless of the device supply, a maskable INT output that flags any change of input state, a 3 V input switching threshold for robust noise immunity, and SPI compatibility up to 5 MHz. The Q900 suffix and /Q900,118 ordering code identify the automotive AEC-Q100 compliant variant with extended -40 C to +125 C operation; NXP states that PCA9703PW/Q900 is AEC-Q100 compliant and PPAP documentation is available via i2c.support@nxp.com. Technically, the PCA9703 samples its 16 GPI inputs into an internal shift register and shifts data out on MISO under host control of CS and SPI clock. Any input change (open, closed, or 12 V/24 V level via divider) triggers the interrupt output, which can be masked to prevent nuisance CPU wake-ups. The low-power CMOS process keeps static consumption minimal, which is critical for always-on battery-backed switch monitoring. Typical applications include automotive switch monitoring (door, window, seat, and steering-column switches), industrial control panels and limit-switch monitoring, and 12 V/24 V system status sensing where contacts ride on battery-level rails the chip inputs directly tolerate. A key design consideration is input threshold scaling: although inputs tolerate 18 V, the 3 V threshold means designers must confirm logic levels and switch pull-up arrangements so that a valid LOW is below threshold and a valid HIGH is safely above it across temperature. This page synthesizes distributor pricing, lifecycle status, drop-in alternative analysis, and practical design notes not found in the manufacturer datasheet alone.
PCA9703PW/Q900,118 - 16-Bit SPI GPI 18V Tolerant | NXP
The NXP Semiconductors PCA9703PW/Q900,118 is an 18 V tolerant SPI 16-bit General Purpose Input (GPI) shift register with maskable interrupt output, supplied in a 24-pin TSSOP package rated for -40 C to +125 C automotive operation with a 4.5 V to 5.5 V supply and a 5 MHz SPI clock. A general purpose input shift register is a specialized interface IC that converts parallel logic levels from switches or sensors into a serial data stream. In the system hierarchy it sits between raw switch inputs and a microcontroller: instead of dedicating 16 MCU pins to switch monitoring, a single SPI port reads all 16 inputs as a serial word, reducing pin count, wiring harness complexity, and cost in distributed control systems. Key features include 18 V tolerance on all GPI pins, allowing direct connection to automotive battery-nominal rails without level shifting; a maskable interrupt output (INT) with an INT_EN pin that disables the inputs and interrupt to minimize battery drain in cyclically powered systems; and an SDIN pin with pull-down that supports daisy-chaining multiple devices on a single SPI bus for 32, 48, or more inputs. Architecturally, the PCA9703 uses a shift register with a dedicated output enable controlled by CS. The 3 V logic thresholds on the serial interface ensure compatibility with both 3.3 V and 5 V controllers. Switch status is captured in the parallel input register and shifted out MSB-first on SCLK edges, with the interrupt flag readable on the first serial byte so the MCU can branch quickly on any input change. Typical applications include automotive switch monitoring for door, seat, and steering-column controls, body control modules and keypads, and industrial panels requiring isolated or battery-tolerant digital inputs. The 18 V tolerance is the decisive parameter wherever switches are wired to unregulated supply rails. A key design consideration: the GPI inputs require external pull-up or pull-down resistors to the switched rail; the INT_EN pin should be driven low during system sleep to eliminate quiescent current drawn through those resistors. This page synthesizes distributor pricing, drop-in alternative analysis, design notes, and application guidance not found in the manufacturer datasheet, making it a one-stop engineering reference for the PCA9703PW/Q900,118.
PCA9704PW/Q900 - 8-bit SPI GPI 18V Tolerant | NXP
The NXP Semiconductors PCA9704PW/Q900 is an 8-bit, 18 V tolerant SPI General Purpose Input (GPI) shift register with maskable interrupt, AEC-Q100 qualified for automotive applications, housed in a 16-pin TSSOP (PW) package. It monitors the status of switch inputs and reads them out over a standard SPI interface running at up to 5 MHz. A general-purpose input expander is an interface IC that offloads switch or status-signal monitoring from a microcontroller. In the signal-chain hierarchy, the PCA9704 sits between discrete switch contacts and an MCU's SPI peripheral: GPIO expander -> interface IC -> mixed-signal logic device. Input expanders are used when an MCU lacks sufficient input pins or when switch signals sit at voltages higher than the MCU supply, as is common in automotive 12 V and 24 V electrical systems. Key features include eight input channels each tolerant to 18 V, allowing direct connection to battery-referenced switch contacts without external level shifting or clamping networks. The SPI interface supports read-out at up to 5 MHz, and a maskable interrupt output (INT) alerts the host controller only when inputs change, enabling low-power polled or event-driven system architectures. Technically, the PCA9704 is implemented as a parallel-in serial-out shift register with input latching. When the host asserts the chip-select, the current input state is latched and shifted out on the SPI data line; devices can be cascaded to expand beyond eight inputs on a single SPI bus. The /Q900 suffix denotes NXP's automotive product-line extension with AEC-Q100 compliance and PPAP support, distinguishing it from the commercial-grade PCA9704PW. Typical applications include automotive switch monitoring (door, seat, and key contacts), industrial control-panel status readback, and system diagnostics where battery-level fault or presence signals must be safely captured by a low-voltage controller. Design consideration: although the 18 V tolerance removes the need for input dividers, verify worst-case battery load-dump transients in automotive systems and confirm that the interrupt mask register is initialized before enabling INT to avoid spurious wake-ups at power-up. This page synthesizes distributor data, automotive-grade alternative options, and practical SPI integration notes not found in the manufacturer datasheet, with pricing verified as of 2026-10-19.