Interface ICs
Subcategories
Products (3,400+)
PCAL6408AHK - 8-Bit I2C I/O Expander, XQFN-16 | NXP
The NXP Semiconductors PCAL6408AHK is a low-voltage translating, 8-bit general-purpose I/O expander with interrupt output, reset, and Agile I/O configuration registers, interfacing to a host microcontroller via I2C-bus/SMBus at up to 400 kHz in a 16-pin XQFN (1.8 x 2.6 mm) package. An I/O expander is a peripheral IC that adds extra general-purpose input/output pins to a microcontroller or embedded processor over a serial bus such as I2C or SMBus. In the system hierarchy, it sits within the interface IC family, under mixed-signal peripheral devices, and complements microcontrollers whose native GPIO count is exhausted. Expanders offload GPIO expansion while consuming only two bus wires (SDA, SCL), conserving processor pins and board routing. Key features include a wide supply range of 1.65 V to 5.5 V, dual power rails for true voltage level translation between logic domains, programmable output drive strength, and latchable inputs. The interrupt output and active-low reset provide robust event-driven and fault-recovery behavior in multi-slave I2C systems. The Agile I/O feature set - configurable output drive, input latch, and pull-up/pull-down enable - allows system designers to tune signal integrity and power per pin, which is significant in mixed-voltage designs where a 1.8 V MCU must safely drive 3.3 V or 5 V peripherals. Open-drain and push-pull operating modes over I2C/SMBus at 400 kHz provide flexible bus integration. Typical applications include GPIO expansion in portable and battery-powered devices, level translation between low-voltage processors and legacy 5 V peripherals, sensor and keypad scanning, LED control, and backplane status monitoring in industrial systems. Design consideration: because the XQFN-16 package measures only 1.8 x 2.6 mm, the exposed pad must be soldered to a grounded PCB land pattern for reliable thermal and mechanical performance; verify land-pattern tolerances before assembly. This page synthesizes distributor pricing context, drop-in alternatives, practical design notes, and AEO-optimized FAQs not found in the NXP datasheet.
PCF85176T/1 - 40x4 LCD Segment Driver I2C TSSOP-56 | NXP
The NXP Semiconductors PCF85176T/1 is a universal LCD segment driver with 40 segments and 4 backplanes, packaged in a 56-pin TSSOP (TSSOP-56). It interfaces to almost any Liquid Crystal Display (LCD) with low multiplex rates via an I2C-bus and generates the drive signals required for static or multiplexed LCDs up to 4x40. The device supports a frame frequency of 82 Hz and is widely used where cascadable LCD expansion is needed. A segment driver (LCD driver) is a peripheral device that translates digital commands from a microcontroller into the multi-level AC waveforms required to drive a passive-matrix liquid crystal display. LCD segment drivers sit in the display driver hierarchy above simple character LCD modules, providing designers with a low-pin-count way to control custom glass through bias generation, backplane sequencing, and segment latching. The PCF85176T/1 combines on-chip bias generation with a serial I2C interface so an MCU only needs two I/O lines to address 160 individual pixel segments. Key features include 40 segment outputs plus 4 backplane outputs (160 pixel capability), integrated charge-pump-based LCD bias voltage generator, selectable bias modes for static, 2-way, 3-way, and 4-way multiplexing, an I2C-bus interface with hardware-selectable slave addresses for cascading, on-chip oscillator requiring no external components, and a wide logic supply range compatible with 3.3 V and 5 V microcontrollers. The CMOS process and TSSOP-56 footprint keep the part economical for mid-volume industrial and consumer LCD designs. The architecture consists of an I2C slave controller, a display RAM of 80 bits (40 segments x 2 pages), a programmable frame frequency generator, and a segment/backplane driver block tolerant of liquid crystal threshold voltages typically between 3 V and 9 V. The integrated VLCD generator eliminates the need for an external DC-DC converter in many designs, reducing BOM cost and PCB area. Typical applications include point-of-sale (POS) terminals, industrial control panels with character or numeric LCDs, white-goods user interfaces such as washing machines and microwave ovens, automotive instrument cluster sub-displays, medical instrument readouts, and metering equipment (water/gas/electricity meters). Cascading multiple PCF85176T/1 devices enables larger glass panels, supporting display sizes up to 320 segments in a chain. When designing with this part, use the on-chip bias generator to produce VLCD rather than an external rail, and reserve one I2C address bit per cascaded chip. Designers should also enable the internal oscillator unless precise frame frequency synchronization is required by the application.
PCF8562TT/2 - 4x32 I2C LCD Segment Driver | NXP | TSSOP-48
The NXP PCF8562TT/2 is a universal LCD segment driver with 4 backplanes and 32 segments, controlled via the two-line bidirectional I2C-bus, housed in a 48-pin TSSOP (SOT362-1) package. It supports supply voltages of 2.5V, 3.3V, and 5V, a typical frame frequency of 64 Hz, and operating temperatures from -40C to +85C. The CMOS device drives static, 2-way, 3-way, or 4-way multiplexed LCDs with selectable static, 1/2, or 1/3 bias configuration. An LCD segment driver is an integrated circuit that generates the AC voltage waveforms required to drive individual segments of a liquid-crystal display. It sits hierarchically between the microcontroller (which decides what to display) and the LCD glass (which physically renders pixels). The PCF8562 belongs to the LCD driver family, which is a subcategory of display driver ICs, itself part of the broader power management and interface semiconductor landscape. Because it uses I2C and runs from a single low-voltage rail, it is a common choice in battery-powered and embedded designs. Key features include selectable backplane drive configuration (static, 2, 3, or 4 backplane multiplexing), selectable display bias configuration (static, 1/2, or 1/3), and a 64 Hz typical frame frequency that minimizes flicker for direct-driven LCDs. The device integrates charge-pump-based bias generation and can drive up to 128 segments in 4-mux mode (4 backplanes x 32 segments). Automotive-grade variants such as PCF8562TT/S400/2 carry AEC-Q100 compliance, making the family suitable for dashboard clusters and instrument panels. From a technical depth perspective, the PCF8562 uses CMOS technology to minimize quiescent current, supports cascadable I2C clock stretching, and includes an internal oscillator with external resistor adjustment. The architecture separates the I2C slave logic (pins SDA, SCL, SA0) from the high-voltage LCD driver outputs (BP0-BP3, S0-S31), allowing the digital core to operate at logic levels while the segment outputs swing to VLCD. Designers typically pair the PCF8562 with a host MCU such as the LPC family or general-purpose microcontrollers using only two GPIO pins for the entire interface. Typical applications include metering displays (electricity, water, gas meters), white goods front panels, point-of-sale terminals, automotive instrument clusters (with the /S400/2 variant), medical device readouts, and any low-multiplex-rate character or graphic LCD up to 32 segments per chip. Two or more PCF8562 devices can share a single I2C bus by using different SA0 slave-address straps. The 48-pin TSSOP footprint makes it compatible with hand-solderable prototypes and high-density production boards alike. When designing with the PCF8562, ensure VLCD is properly bypassed with a 100 nF ceramic capacitor and that BP0-BP3 traces are kept short to reduce display ghosting. Designers should also verify the slave address selection via the SA0 pin to avoid bus conflicts when cascading multiple drivers. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
PCF8574ADW - 8-Bit 5.5V I2C I/O Expander | Texas Instruments
Texas Instruments PCF8574ADW is an 8-bit I2C/SMBus input/output expander operating from 2.5 V to 5.5 V, supporting I2C communication at 100 kHz in a 16-pin SOIC (DW) package. It adds eight quasi-bidirectional I/O ports and an interrupt output to a host controller, reducing the number of GPIO pins required by embedded systems. An I/O expander is an interface IC that extends the input/output capacity of a host such as a microcontroller or application processor. The PCF8574 belongs to the I2C I/O expander hierarchy and uses the two-wire bus for command and status transfers. Eight ports can be individually configured as inputs or outputs, while address pins allow multiple expanders to coexist on the same bus. Key features include eight I/O lines, a 2.5 V to 5.5 V operating range, 100 kHz I2C operation, and an open-drain interrupt output. The interrupt output allows the connected processor to respond when a change occurs on an input port rather than continuously polling all eight lines. The SOIC-16 package supports conventional surface-mount assembly and is available in a -40 °C to +85 °C temperature grade. The PCF8574A architecture uses quasi-bidirectional ports capable of both input and output operation. Each port can be driven low or released high, while an external pull-up resistor is normally required to establish the high state. The three address inputs select one of eight device addresses, allowing several PCF8574 devices to share common SCL and SDA nets. Power-on behavior depends on the external pull-up network and must be considered when defining system defaults. Typical uses include reading control buttons and switches, driving discrete LEDs, monitoring digital status signals, and expanding the GPIO capacity of industrial controllers, test equipment, access-control panels, and compact embedded products. The interrupt line is especially useful in systems where periodic I2C polling would waste processor time or create unnecessary bus activity. Design the interface around the device's open-drain bus architecture. Place pull-up resistors on SDA and SCL close to the bus master, confirm address-strapping levels before enabling the device, and account for the port high-current limitations when driving capacitive or LED loads. The manufacturer datasheet is the controlling reference for pinout, timing, output-current limits, and electrical characteristics.
PCF8574AN - 8-Bit I/O Expander | Texas Instruments | DIP
The Texas Instruments PCF8574AN is an 8-bit remote I/O expander intended for digital input and output expansion in embedded systems. The device communicates with a host controller through a two-wire serial interface and provides eight separately addressable I/O lines. It is supplied in a 16-pin dual in-line package, with the AN order suffix identifying the packaged variant. This addressable I/O architecture places the PCF8574AN in the interface IC hierarchy: serial interface controller, I/O expander, embedded-system interface, and semiconductor. A remote I/O expander reduces the number of general-purpose I/O pins required on a microcontroller, programmable logic controller, or other embedded controller. Eight digital lines can be distributed across a remote circuit board, allowing buttons, indicators, logic inputs, or other digital signals to connect to a shared two-wire bus. The PCF8574AN therefore reduces package size and routing complexity when a design requires more digital interface lines than the host controller provides directly. The verified dataset supplied for this product contains no manufacturer-document specifications or distributor records. Consequently, operating voltage, address range, output-drive capability, clock frequency, logic thresholds, quiescent current, and environmental ratings are not asserted on this page. These parameters must be confirmed from the applicable Texas Instruments manufacturer datasheet before the IC is used in a new schematic, PCB layout, firmware configuration, or safety- and reliability-critical design. The PCF8574AN is typically associated with 5 V and 3.3 V embedded systems, but the actual supported supply range and interface levels are deliberately left unspecified here because no verified manufacturer data was provided. Logic-level compatibility must be evaluated using the authoritative input thresholds, output leakage, and output-driver specifications rather than nominal rail voltage alone. Typical design candidates include general-purpose microcontroller I/O expansion, programmable controller input modules, front-panel button and indicator handling, and simple industrial control boards. An I2C or other two-wire host bus may be shared by multiple expanders only after address allocation, electrical loading, pull-up requirements, and bus-speed limits have been verified. The primary layout concern is the two-wire bus. Place pull-up resistors and decoupling capacitors close to the appropriate bus endpoints, keep the clock and data traces short, and confirm that every connected device can tolerate the selected voltage and clock rate. Firmware must also establish the device address and configure each line as input or output before external hardware is energized. This page combines an authenticity-first specification record with procurement, replacement, selection, and design-intent guidance. Because the retrieved distributor and cross-reference searches returned no records, market pricing, lifecycle availability, exact pin naming, and additional drop-in alternatives remain explicitly unverified rather than being inferred from similar devices.
PCF8574APW - 8-Bit I2C I/O Expander | Texas Instruments
Texas Instruments PCF8574APW is an 8-bit I2C/SMBus remote I/O expander with interrupt support, a 2.5 V to 5.5 V operating-voltage range, and a 20-pin TSSOP package. It adds eight quasi-bidirectional port lines to a host microcontroller through a two-wire serial interface, making it useful when a controller has insufficient general-purpose I/O pins. An I/O expander is an interface IC that translates serial bus commands into parallel digital input and output access. The PCF8574A family belongs to the I/O expander category within interface ICs, interface semiconductors, and electronic components. Its remote port can connect to buttons, indicators, logic inputs, control signals, and other digital peripherals while the host processor retains access through the I2C bus. The device provides eight quasi-bidirectional I/O pins, an interrupt output, three hardware address inputs, and operation from 2.5 V to 5.5 V. According to the Texas Instruments PCF8574A product page, the device supports both I2C and SMBus communication. The manufacturer datasheet also identifies a maximum standby-current consumption of 10 microamperes, supporting designs where standby power is an important consideration. The A designation identifies the address-selectable version of the PCF8574 family. Each device offers three address inputs, allowing multiple expanders to share one serial bus when suitable bus addresses are assigned. The interrupt output provides a hardware indication that input-port state has changed, reducing the need for the host controller to poll every port continuously. Typical uses include expanding microcontroller GPIO for human-interface controls, monitoring switches and keypads, driving LEDs or logic-enable signals, controlling discrete system inputs, and supporting industrial interface modules. It can also reduce the number of I/O pins required on a microcontroller, processor, or programmable logic controller. A hardware design should treat the quasi-bidirectional port outputs carefully because each line may be weakly driven high and can be pulled low by an external device. Designers should review the port architecture, address pins, bus pull-up requirements, and interrupt behavior in the manufacturer datasheet before finalizing the circuit. This product page combines the manufacturer electrical characteristics, interface details, application guidance, pin assignment information, and verified substitute analysis. It also highlights the limits of direct replacement: identical pin count and package dimensions alone do not guarantee that two I/O expanders use identical addressing, interrupt, electrical, or qualification behavior.
PCF8574AT/3,518 - 8-bit I2C I/O Expander | NXP SOIC-16
The NXP PCF8574AT/3,518 is an 8-bit I/O expander with quasi-bidirectional I/O pins, an I2C-bus interface operating up to 100 kHz, and an open-drain interrupt output, housed in a 16-pin SO (SOIC-16, MS-013/SOT-162-1) plastic package. It operates from 2.5 V to 6 V supply, supports three hardware address pins (A0-A2), and provides a different fixed I2C address base than the PCF8574 (0x3F for the PCF8574A family vs 0x20 for the PCF8574A base, allowing up to eight of each on the same bus). The CMOS silicon-gate design draws low quiescent current (typ. 40 uA) and supports a maximum of 16 PCF8574/PCF8574A devices on one shared I2C-bus, expanding up to 128 I/Os. An I/O expander is a class of digital peripheral IC that extends the limited GPIO count of a host microcontroller through a serial bus, allowing additional inputs, outputs, keypads, LED indicators, and signal-conditioning lines without increasing pin count on the MCU. Within the hierarchy of interface ICs (also called bus expanders or GPIO extenders), the PCF8574AT belongs to the I2C-bus parallel-port family, positioned between simple shift-register expanders (which lack interrupt capability) and full SPI/I2C port-mapped devices. This category sits under digital logic and interface ICs in broader semiconductor taxonomy, supporting both consumer and industrial designs where MCU pin count is constrained. Key features include quasi-bidirectional I/O that can directly drive LEDs without external pull-ups (sinking capability of up to 25 mA per pin, max 100 mA total), an active-low interrupt output (INT) that signals the host when any input state changes, and 400 kHz Fast-mode I2C capability on the PCF8574A/PCF8574AT family variants. The device integrates a noise filter on the SCL/SDA lines and supports clock stretching as a slave device. The PCF8574AT uses a CMOS silicon-gate architecture with latched output registers and input latches on every I/O pin. The quasi-bidirectional design uses a weak pull-up (typically 100 uA current source) to drive outputs high; pulling low requires the pin to actively sink current. This architecture eliminates the need for external pull-up resistors on outputs while maintaining low standby current. Typical applications include driving LED arrays, LCD segment interfaces, keypad matrix scanning, fan-speed monitoring, relay control boards, and general-purpose I2C slave peripheral expansion in industrial control, consumer electronics, and embedded systems. Engineers commonly pair the PCF8574AT with low-power MCUs (such as the LPC1100 or PIC16F families) to add 8-bit digital I/O over only two signal wires. When designing with this part, note that the quasi-bidirectional I/O pins have an asymmetric drive capability - they source weakly (100 uA) but sink strongly (25 mA per pin). This makes them ideal for LED-driving (sink mode) but less suitable as push-pull signal drivers. Always respect the absolute maximum of 100 mA total current through the VDD/GND pins to avoid latch-up. This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet alone, including cross-references for the very similar PCF8574T/3 (different I2C address range).
PCF8574DW - 8-Bit 100kHz I2C I/O Expander | Texas Instruments
Texas Instruments PCF8574DW is an 8-bit I2C I/O expander with a 100 kHz bus, eight quasi-bidirectional ports, and an interrupt output, supplied in a 16-SOIC package. According to the manufacturer product page, it supports 2.5 V to 5.5 V operation, while the manufacturer datasheet search result describes 2.5 V to 6 V VCC operation. The device adds eight parallel digital lines to a host microcontroller without consuming eight dedicated GPIO pins. An I/O expander is an interface IC that translates serial I2C commands into parallel digital inputs or outputs. The PCF8574 belongs to the parallel-port expansion and I2C interface hierarchy. It uses two bus lines, SCL and SDA, to receive configuration and port-state data from a microcontroller, then presents P0 through P7 as individually controlled digital ports. Its interrupt output allows a host to react when an input condition changes without continuously polling the bus. The principal features include eight I/O ports, a maximum I2C clock frequency of 100 kHz, a 2.5 V to 6 V VCC operating range stated in the datasheet, and low standby-current consumption with a listed maximum standby current of 10 µA. The open-drain interrupt output is compatible with common microcontroller interrupt inputs. The 16-SOIC package is a surface-mount SOIC-16 footprint, and the DWR tape-and-reel ordering code must not be confused with the DW tube ordering code. The quasi-bidirectional port architecture makes the PCF8574 useful for simple control and status signals. A port can be written as an output or sampled as an input, but the electrical behavior and pull-up implementation require care when driving external loads. The interrupt pin provides an event-oriented alternative to periodic reads when one or more input lines change state. Firmware must also verify the device address and bus pull-up arrangement when multiple expanders share the same two-wire bus. Typical applications include keypad and control-panel scanning, relay or solenoid control, LED indication, sensor and switch input aggregation, industrial control modules, and general embedded systems where a microcontroller has too few GPIO pins. The expander is particularly useful when the required signals are simple logic levels and the bus is already present. It is less suitable when high-speed edge-sensitive inputs, high-current output drive, or strong isolation requirements are present. Designers should verify pull-up resistors on SDA and SCL, ensure that all connected devices use compatible voltage levels, and account for total bus capacitance. Port pins intended as inputs should not be forced into incompatible logic states, while output loads should remain within verified current and voltage limits. This page combines the supplied manufacturer and distributor data with practical design guidance, comparison parameters, and sourcing information.
PCF8574DWR - 8-Bit 100kHz I2C I/O Expander | Texas Instruments (Tape & Reel)
Texas Instruments PCF8574DWR is an 8-bit I2C I/O expander with a 100 kHz bus, eight quasi-bidirectional ports, and an interrupt output, supplied in a 16-SOIC package. According to the manufacturer product page, it supports 2.5 V to 5.5 V operation, while the manufacturer datasheet search result describes 2.5 V to 6 V VCC operation. The device adds eight parallel digital lines to a host microcontroller without consuming eight dedicated GPIO pins. An I/O expander is an interface IC that translates serial I2C commands into parallel digital inputs or outputs. The PCF8574 belongs to the parallel-port expansion and I2C interface hierarchy. It uses two bus lines, SCL and SDA, to receive configuration and port-state data from a microcontroller, then presents P0 through P7 as individually controlled digital ports. Its interrupt output allows a host to react when an input condition changes without continuously polling the bus. The principal features include eight I/O ports, a maximum I2C clock frequency of 100 kHz, a 2.5 V to 6 V VCC operating range stated in the datasheet, and low standby-current consumption with a listed maximum standby current of 10 µA. The open-drain interrupt output is compatible with common microcontroller interrupt inputs. The 16-SOIC package is a surface-mount SOIC-16 footprint, and the DWR tape-and-reel ordering code must not be confused with the DW tube ordering code. The quasi-bidirectional port architecture makes the PCF8574 useful for simple control and status signals. A port can be written as an output or sampled as an input, but the electrical behavior and pull-up implementation require care when driving external loads. The interrupt pin provides an event-oriented alternative to periodic reads when one or more input lines change state. Firmware must also verify the device address and bus pull-up arrangement when multiple expanders share the same two-wire bus. Typical applications include keypad and control-panel scanning, relay or solenoid control, LED indication, sensor and switch input aggregation, industrial control modules, and general embedded systems where a microcontroller has too few GPIO pins. The expander is particularly useful when the required signals are simple logic levels and the bus is already present. It is less suitable when high-speed edge-sensitive inputs, high-current output drive, or strong isolation requirements are present. Designers should verify pull-up resistors on SDA and SCL, ensure that all connected devices use compatible voltage levels, and account for total bus capacitance. Port pins intended as inputs should not be forced into incompatible logic states, while output loads should remain within verified current and voltage limits. This page combines the supplied manufacturer and distributor data with practical design guidance, comparison parameters, and sourcing information.
PCF8574N - 8-Bit 100kHz I2C I/O Expander | Texas Instruments
The Texas Instruments PCF8574N is an 8-bit bidirectional I/O expander for the I2C bus, operating from 2.5V to 6V with a 100kHz interface and housed in a 16-pin PDIP package. It adds eight quasi-bidirectional remote I/O lines to a host microcontroller while providing open-drain interrupt signaling. The device is designed for general-purpose expansion across embedded control, communications, and embedded accessory designs. What is an I2C I/O expander? An I/O expander is an interface IC that translates serial bus commands into parallel digital signals. The PCF8574N belongs to the I/O-expander class, which sits within interface ICs and broader semiconductor systems. It helps a controller with too few GPIO pins operate additional buttons, indicators, relays, or other digital peripherals while preserving a shared SDA and SCL bus. Key features include eight I/O ports, 100kHz I2C operation, a 2.5V to 6V supply range, and an interrupt output. Its quasi-bidirectional ports can be configured as inputs or outputs, while power-on behavior and external pull-up requirements must be considered in the system design. The verified distributor listing identifies the PCF8574N as an 8-bit, 100kHz I/O expander in a PDIP package. The device uses the PCF8574 family architecture in which the host communicates over the two-wire I2C bus and reads or writes the remote port state. Because the ports are quasi-bidirectional rather than independently powered high-impedance inputs and outputs, firmware and external circuitry should avoid contention scenarios. The interrupt line provides a hardware indication that input data has changed, reducing unnecessary serial polling when the application supports it. Typical applications include microcontroller GPIO expansion, keypad and control panels, relay or indicator interfaces, industrial automation modules, communications equipment, and embedded systems using the site-listed STM32, ATMEGA, MSP430, or other microcontroller families. The same I2C bus can support multiple addressed peripherals, subject to the device address configuration and bus capacitance requirements. Designers should follow the manufacturer datasheet for pull-up resistor selection, address strapping, decoupling, input/output polarity, and interrupt handling. Confirm the available voltage range against the connected bus and peripherals, and verify absolute maximum ratings before using the device in systems with long cables or exposed connectors. The 16-pin PDIP package favors through-hole prototyping rather than compact surface-mount production. This page combines the verified manufacturer and distributor information for PCF8574N with package, selection, design, and application guidance. It is intended to help engineers identify whether the part fits a particular I2C expansion requirement before comparing alternatives or requesting supply.
PCF8574NG4 - 8-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCF8574NG4 is an 8-bit I/O expander for the two-line bidirectional I2C bus, operating from 2.5 V to 6 V VCC at a maximum bus frequency of 100 kHz. It is housed in a 16-pin PDIP package measuring 0.300 inches with 7.62 mm lead spacing. The device expands one I2C controller into eight quasi-bidirectional GPIO lines for sensors, relays, switches, logic controls, and other external interfaces. An I/O expander is an interface IC that extends the number of general-purpose inputs and outputs available to a microcontroller or other host processor. The I2C interface uses serial clock and serial data lines to transfer address and port information, while the parallel port provides individual connections to external hardware. This hierarchy places the PCF8574 within I2C interface controllers, interface ICs, and semiconductor-based system expansion components. The PCF8574 combines an 8-bit quasi-bidirectional port with an I2C interface. Quasi-bidirectional operation means each port can be used for input or output, with output drivers capable of sinking current while the input state can be detected. An interrupt output provides a way for the host to react when a changing input condition is detected, reducing the need for continuous I2C polling in suitable designs. The 2.5 V to 6 V VCC range allows the device to operate with both 3.3 V and 5 V system rails. Its 100 kHz I2C maximum supports conventional standard-mode bus operation and broad compatibility with embedded processors. The remote port also reduces the number of GPIO pins required from the host controller, which can simplify pin allocation in compact embedded systems. Typical uses include relay and solenoid control, keypad and switch sensing, LED or indicator interfaces, sensor input collection, and industrial control panels. The same electrical interface is useful when the remote equipment is physically separated from the host because the PCF8574 communicates through the bus while exposing local input and output connections at the port. Design with the port's quasi-bidirectional characteristics and the electrical limits in the manufacturer datasheet in mind. Pull-up requirements, address selection, bus capacitance, output-driver topology, and reset behavior must be checked against the specific system. Do not assume that every quasi-bidirectional port can source the same current that it can sink. This page combines the manufacturer electrical operating range, package details, pin-level guidance, and application-oriented analysis with a focused comparison of verified same-package alternatives. It also identifies design trade-offs that are not obvious from a distributor category listing, helping engineers determine whether the 16-pin PCF8574NG4 remains suitable for a new embedded interface design.
PCF8574PW - 8-bit I2C I/O Expander 20-TSSOP | Texas Instruments (Tape & Reel)
The Texas Instruments PCF8574PW is a remote 8-bit I/O expander for the I2C bus, designed for 2.5 V to 6 V VCC operation, packaged in a 20-pin TSSOP (PW) with Tape and Reel packaging. It provides general-purpose remote I/O expansion for most microcontroller families via the I2C interface (serial clock SCL, serial data SDA) and supports an interrupt (INT) output to flag input changes to the host. An I/O expander is a type of interface IC that sits between a host controller (typically a microcontroller with limited GPIO) and external peripherals, translating a serial bus into multiple parallel digital lines. The PCF8574 belongs to the I2C I/O expander family -> interface IC -> integrated circuit -> semiconductor. By cascading multiple devices, designers can scale I/O count without redesigning the host board, making I/O expanders essential in space-constrained and pin-limited embedded designs. Key features include 8 quasi-bidirectional I/O pins, 100 kHz I2C clock rate, three hardware address pins (A0-A2) allowing up to 8 devices on the same bus (16 combined with PCF8574A), an active-low interrupt output that wakes the host on input changes, and low standby current of 2.5 uA typical. The PCF8574 uses the I2C address base 0x20 (PCF8574A uses 0x38), supporting up to 16 devices on a single bus for 128 I/Os. The quasi-bidirectional I/O architecture eliminates the need for a direction control register by using a clever pull-up/pull-down scheme, simplifying firmware. Each I/O can source 25 mA (LED drive capability) and sink up to 25 mA, sufficient to drive LEDs, keypads, or relay coils directly without buffering. Typical applications include keypad scanning for human-machine interfaces, LED driving for status indicators and display backlights, GPIO expansion for Raspberry Pi or ESP32-based projects, and industrial control panels. The wide 2.5 V to 6 V VCC range allows interfacing with both 3.3 V and 5 V logic without level shifters. When designing with this device, note that quasi-bidirectional I/Os are weak when transitioning to high - add an external pull-up resistor (typically 10 kohm) if driving heavy capacitive loads. The INT pin must be acknowledged by the host to clear the interrupt condition. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
PCF8574PWR - 8-bit I2C I/O Expander 20-TSSOP | Texas Instruments
The Texas Instruments PCF8574PWR is a remote 8-bit I/O expander for the I2C bus, designed for 2.5 V to 6 V VCC operation, packaged in a 20-pin TSSOP (PW) with Tape and Reel packaging. It provides general-purpose remote I/O expansion for most microcontroller families via the I2C interface (serial clock SCL, serial data SDA) and supports an interrupt (INT) output to flag input changes to the host. An I/O expander is a type of interface IC that sits between a host controller (typically a microcontroller with limited GPIO) and external peripherals, translating a serial bus into multiple parallel digital lines. The PCF8574 belongs to the I2C I/O expander family -> interface IC -> integrated circuit -> semiconductor. By cascading multiple devices, designers can scale I/O count without redesigning the host board, making I/O expanders essential in space-constrained and pin-limited embedded designs. Key features include 8 quasi-bidirectional I/O pins, 100 kHz I2C clock rate, three hardware address pins (A0-A2) allowing up to 8 devices on the same bus (16 combined with PCF8574A), an active-low interrupt output that wakes the host on input changes, and low standby current of 2.5 uA typical. The PCF8574 uses the I2C address base 0x20 (PCF8574A uses 0x38), supporting up to 16 devices on a single bus for 128 I/Os. The quasi-bidirectional I/O architecture eliminates the need for a direction control register by using a clever pull-up/pull-down scheme, simplifying firmware. Each I/O can source 25 mA (LED drive capability) and sink up to 25 mA, sufficient to drive LEDs, keypads, or relay coils directly without buffering. Typical applications include keypad scanning for human-machine interfaces, LED driving for status indicators and display backlights, GPIO expansion for Raspberry Pi or ESP32-based projects, and industrial control panels. The wide 2.5 V to 6 V VCC range allows interfacing with both 3.3 V and 5 V logic without level shifters. When designing with this device, note that quasi-bidirectional I/Os are weak when transitioning to high - add an external pull-up resistor (typically 10 kohm) if driving heavy capacitive loads. The INT pin must be acknowledged by the host to clear the interrupt condition. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
PCF8574T - 8-bit I2C I/O Expander, SOIC-16 | NXP Semiconductors
The NXP Semiconductors PCF8574T is a remote 8-bit CMOS I/O expander for the two-line bidirectional I2C-bus, supporting 2.5V to 6V VCC operation and providing general-purpose remote I/O expansion for most microcontroller families. The PCF8574T integrates a quasi-bidirectional 8-bit parallel I/O port (P0-P7), an I2C-bus interface, and a hardware interrupt output (INT) that signals the host controller when input state changes, all in a 16-pin SOIC surface-mount package. What is an I/O expander? An I/O expander is an integrated circuit that adds additional general-purpose input/output pins to a microcontroller through a serial bus (typically I2C or SPI). It sits in the hierarchy: GPIO extender -> I/O expander -> interface IC -> digital semiconductor. The PCF8574T specifically uses a quasi-bidirectional I/O architecture that eliminates the need for a direction control register - each pin can be used as either input or output without explicit mode configuration. Key features of the PCF8574T include three hardware address pins (A0-A2) that allow up to 8 PCF8574T devices to share the same I2C-bus (selectable I2C addresses 0x20-0x27). The quasi-bidirectional I/O architecture requires no direction register, simplifying software drivers. The open-drain interrupt output (INT) is asserted when any input changes, enabling efficient event-driven polling. The device operates across 2.5V-6V VCC, supports I2C standard-mode (100 kHz) and fast-mode (400 kHz), and consumes very low standby current. The PCF8574T uses a silicon CMOS process with an open-drain interrupt line and open-drain bidirectional I/O pins. The quasi-bidirectional architecture drives a weak pull-up (current source) when outputs are HIGH and a strong pull-down when LOW, allowing the same pin to be read back without changing direction. The I2C slave address is programmed via A0, A1, A2; slave base address is 0x20 for PCF8574 and 0x38 for PCF8574A - this distinction is critical when selecting between variants. Typical applications include keypad scanning on human-machine interfaces (HMIs), LED driving on display panels and indicator boards, LCD bias generation, sensor monitoring via additional GPIOs, and adding GPIOs to small microcontrollers. The 0x20-0x27 address range also makes it ideal for multi-bus I/O expansion where multiple expanders must coexist. When designing with the PCF8574T, add 100 kohm pull-up resistors on SDA and SCL because the PCF8574T uses open-drain drivers (no internal pull-ups). Note that the "T" suffix denotes the SOIC-16 package, while "N" denotes DIP-16 and "BS" denotes SSOP-16 - same silicon die, different packages. The PCF8574 (base address 0x20) and PCF8574A (base address 0x38) are NOT drop-in replaceable without changing the host firmware address. This page consolidates distributor pricing, parametric equivalents (TI PCA9534, PCA9554, PCA9557), drop-in alternatives in the SOIC-16 footprint, and practical design notes not found in the manufacturer datasheet.
PCF8574TD - 8-bit I2C I/O Expander, SO-16 | NXP Semiconductors
The NXP PCF8574TD is a remote 8-bit I/O expander for the I2C-bus, supplied in a 16-pin SO (Small Outline) package with a -40C to +85C industrial temperature grade. The device operates from 2.5 V to 6 V VCC and provides eight quasi-bidirectional input/output pins that can be independently assigned as inputs or outputs, all controlled through the standard two-wire I2C interface. An I2C I/O expander is a type of interface IC that sits between a microcontroller and peripheral signals, translating serial commands from the I2C bus into parallel GPIO operations. The PCF8574 belongs to the I/O expander sub-category of interface ICs, itself part of the broader power management and inter-chip communication hierarchy. By adding eight extra quasi-bidirectional ports over only two wires, the PCF8574 lets small microcontrollers control keypads, LCDs, LEDs, and relays without sacrificing native pins for other functions. Key features of the PCF8574TD include a maximum standby current of 10 uA, an open-drain interrupt output (INT) that signals the host when an input changes state, and three hardware address pins (A0-A2) that allow up to eight PCF8574 devices on the same I2C bus (64 I/O lines). The quasi-bidirectional I/O architecture requires no direction-control register: a pin set HIGH is weakly pulled up (~100 uA source), and a pin set LOW is strongly pulled down, simplifying firmware and PCB layout. The PCF8574 uses a fixed I2C slave address of 0x20-0x27 (set by A2:A0), which distinguishes it from the PCF8574A variant (address range 0x38-0x3F). Both share the same SO-16 footprint, enabling dual-sourcing designs. The silicon CMOS process keeps quiescent current low enough for battery-backed applications. Typical applications include keypad scanning, LED driving arrays, LCD module backpacks, relay/Opto-coupler interfacing, and general-purpose GPIO expansion on 8051, ARM Cortex-M, ESP32, PIC, AVR, and MSP430 microcontrollers. The interrupt pin eliminates polling overhead in button or switch-matrix designs. When designing with this device, place a 0.1 uF decoupling capacitor close to VCC and 100 kohm pull-up resistors on SDA, SCL, and INT. Verify your firmware does not read the input port during the I2C ACK bit, as a transient high-current condition can occur on the quasi-bidi pins. This page synthesizes distributor pricing, drop-in alternatives (same-brand NXP variants and cross-brand TI equivalents), and practical design notes that complement, rather than duplicate, the manufacturer datasheet.
PCF8575CDB - 16-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCF8575CDB is a 16-bit I2C/SMBus I/O expander with interrupt output, a 2.5 V to 5.5 V operating range, and a 24-pin SSOP package. It supports I2C operation up to 400 kHz and uses three hardware address pins to allow up to eight devices on one bus. Its open-drain interrupt output provides a low-power way for a connected microcontroller to detect a change on one of 16 remote I/O lines. An I2C I/O expander is a peripheral interface device that converts a serial two-wire connection into additional parallel input or output lines. It belongs to the interface IC hierarchy, where an I/O expander sits between a host microcontroller and external control or sensing circuits. This parallel-to-serial expansion reduces pin count and allows buttons, LEDs, relays, or digital status signals to be connected over a shared bus. The PCF8575CDB provides 16 general-purpose remote I/O lines, three hardware address inputs, SCL and SDA bus connections, an active-low open-drain interrupt output, a 2.5 V to 5.5 V supply range, and operation up to 400 kHz. Three address pins permit eight distinct bus addresses. The interrupt output also supports low standby-current operation, with a maximum standby-current figure of 10 uA identified in the manufacturer documentation. Communication with the device occurs through the two-wire I2C or SMBus-compatible interface. The address pins select the device address without additional external components, while the interrupt line allows the host to avoid continuous polling when a monitored remote input changes state. As a quasi-bidirectional I2C interface, the implementation should be evaluated against the pull-up and bus-drive requirements described in the manufacturer datasheet. Typical uses include expanding microcontroller GPIO for LED indicators and pushbuttons, reading switches and interlocks, controlling relay or solenoid drivers, and building keypad or alarm panels. The 16-bit port is especially useful where a controller must monitor more inputs or drive more outputs than its native package allows. Multiple devices can share the bus when their hardware address pins are configured differently. PCB implementation requires correct pull-up placement for SDA and SCL, unobstructed routing between the expander and its address-setting hardware, and adequate decoupling near the supply pins. Because the interrupt output is open drain, its external pull-up must also be arranged to suit the host’s input and operating voltage. Confirm package pin numbering and signal names against the manufacturer datasheet before finalizing the board layout. This product page combines the manufacturer’s electrical and ordering information with practical implementation guidance, drop-in replacement analysis, and application-oriented design notes. It helps engineers evaluate whether the PCF8575CDB’s 16 lines, addressability, interrupt behavior, and 400 kHz bus capability fit a new embedded control design.
PCF8575CDW - 16-Bit I2C I/O Expander | Texas Instruments
Texas Instruments PCF8575CDW is a 16-bit I2C/SMBus I/O expander with interrupt output, a 2.5 V to 5.5 V operating range, and a 400 kHz bus interface in a 24-pin SOIC package. It adds 16 quasi-bidirectional digital lines to a host microcontroller while requiring only serial clock, serial data, address-selection, power, ground, and interrupt connections. An I/O expander is an interface IC that increases the number of digital input/output lines available to a microcontroller, embedded processor, or other bus controller. Its hierarchy is I/O expander → bus interface expander → digital interface IC → semiconductor. Unlike a dedicated GPIO controller, the PCF8575 family uses a compact I2C/SMBus register interface and quasi-bidirectional ports that can operate as inputs or outputs without separate direction registers. The principal features are 16 independently usable I/O pins, a 2.5 V to 5.5 V supply range, interrupt support, and 400 kHz operation. Each port has latched output capability with high-current drive suitable for directly driving LEDs. At power-on, the I/O pins enter a high state. The interrupt output provides a hardware indication that an input or selected port event requires host attention, reducing unnecessary serial polling. The PCF8575CDW uses a serial protocol compatible with I2C and SMBus systems. Three address-selection pins allow multiple expanders to coexist on the same bus by assigning different device addresses. The 16 quasi-bidirectional lines are organized as P00 through P07 and P10 through P15. Their architecture makes the device practical for translating a compact microcontroller footprint into a larger control interface without adding individual GPIO packages. Typical applications include LED status and signage control, keypad or button matrix interfaces, relay and solenoid control, industrial automation modules, digital sensor gathering, and general-purpose embedded-control boards. The interrupt output is particularly useful when numerous remote inputs must be monitored across multiple PCF8575 devices while keeping the host's serial traffic low. Designers should account for the quasi-bidirectional port architecture, confirm pull-up requirements for SDA and SCL, and ensure the host bus voltage is compatible with the expander's supply. Address pins must be configured before all devices on a shared bus communicate. The 24-pin SOIC footprint also requires adequate spacing between adjacent pins for soldering and inspection. This product page organizes the PCF8575CDW's principal electrical characteristics, pin assignments, interface considerations, same-package replacement candidates, and practical design guidance. It also distinguishes the ordering suffix from functional differences, helping engineers evaluate PCB reuse without relying only on a basic distributor description.
PCF8575CPW - 16-Bit I2C I/O Expander with Interrupt | Texas Instruments
Texas Instruments PCF8575CPW is a 16-bit I2C/SMBus I/O expander with interrupt capability, operating from 4.5 V to 5.5 V and supporting I2C communication up to 400 kHz. It is packaged in a 24-pin TSSOP package, designated PW, for surface-mount PCB designs. An I/O expander is an interface IC that increases the number of general-purpose input and output lines available to a microcontroller or other embedded controller. The PCF8575CPW uses a two-wire serial bus with SCL and SDA signals, allowing 16 quasi-bidirectional ports to be accessed through a compact serial interface. This is particularly useful when a host controller has insufficient GPIO pins for buttons, relays, indicators, or other peripherals. The PCF8575 family provides a 16-bit quasi-bidirectional port and an I2C interface. Its latched outputs support direct LED driving, while the quasi-bidirectional inputs can be read by the host through the serial bus. The device also includes an interrupt output, allowing the connected controller to respond when an input state changes rather than continuously polling every port. The PCF8575CPW is designed for 4.5 V to 5.5 V VCC operation and uses address pins to allow multiple expanders to coexist on the same bus. The I2C interface operates at up to 400 kHz, making the device appropriate for embedded systems, control boards, industrial interfaces, and small peripheral expansion designs. Typical applications include keypad scanners, LED indicator panels, relay and transistor control, sensor and switch input modules, and general-purpose I2C GPIO expansion. The 24-pin TSSOP package supports compact surface-mount layouts, while external pull-up resistors are normally required on SDA and SCL according to the bus implementation guidance in the manufacturer datasheet. For new designs, check the PCF8575CPW pin description table and electrical characteristics in the manufacturer datasheet before assigning PCB tracks or selecting external pull-up resistors. The interrupt line and address pins require careful placement so that multiple expanders can be cascaded without address conflicts. This page combines the manufacturer product information, distributor listing data, package details, comparison references, and application-oriented design guidance to support component selection and PCB implementation.
PCF8575DB - 16-Bit I2C I/O Expander | Texas Instruments
Texas Instruments PCF8575DB is a 16-bit remote I/O expander for I2C and SMBus systems, operating from 2.5 V to 5.5 V with bus speeds up to 400 kHz in a 24-pin SSOP package. Its two 8-bit quasi-bidirectional ports, P07–P00 and P17–P10, can be individually configured as inputs or outputs without a separate data-direction register. The device also includes an open-drain interrupt output and three hardware address inputs, allowing as many as eight devices to share an I2C bus. An I/O expander is an interface IC that extends the number of digital input and output lines available to a microcontroller or other host processor. The PCF8575 belongs to the I2C interface IC hierarchy and uses a serial command-and-data bus to transfer port state over two wires. Its 16 quasi-bidirectional lines can reduce the number of GPIO pins required by a host while remaining suitable for common logic-level inputs, relay-control signals, status indicators, and LED loads. Each quasi-bidirectional I/O has latched output capability and high-current drive for directly driving LEDs. The same line can be read as an input without changing the output latch, although the electrical behavior differs from a conventional push-pull output. At power-on, all I/O ports are high. The three address pins provide hardware-selectable device addresses for a maximum of eight PCF8575 devices on one bus, while the open-drain interrupt output provides a hardware indication of input-port state changes. The interface supports both I2C and SMBus operation, and the verified product information identifies operation up to 400 kHz. Low standby-current consumption is specified at a maximum of 10 µA. These characteristics make the device useful in embedded systems where bus wiring, connector pin count, standby power, or host GPIO availability constrain the design. The 24-pin SSOP, identified by distributor records as SSOP-24 with a 5.30 mm width and 0.209 inch lead spacing, supports compact surface-mount assembly. Typical uses include reading switches and keypads, driving LED indicators, monitoring digital control signals, controlling discrete transistors or relays, and expanding I/O in industrial controllers, appliance controllers, test equipment, and microcontroller boards. Because the interrupt output is open-drain, multiple interrupt-capable devices can share a common signal when the system supports wired-AND behavior. Firmware must also account for the I2C address, port polarity, and quasi-bidirectional input current requirements. The primary design consideration is choosing the pull-up voltage and ensuring that the bus capacitance and wiring permit reliable operation at 400 kHz. I2C pull-up resistors should be placed on the host side of long or branched wiring, and software should acknowledge only the interrupt source determined by the device address. The available verified material does not provide a complete pin table, explicit price values, or detailed absolute-maximum ratings. This product page consolidates the verified manufacturer description, distributor package identification, I2C features, interrupt behavior, power-on state, and available substitute references. It also adds application guidance, engineering caveats, and a transparent distinction between verified specifications and parameters that still require confirmation from the complete manufacturer datasheet.
PCF8575DBR - 16-Bit I2C I/O Expander | Texas Instruments (Tape & Reel)
Texas Instruments PCF8575DBR is a 16-bit remote I/O expander for I2C and SMBus systems, operating from 2.5 V to 5.5 V with bus speeds up to 400 kHz in a 24-pin SSOP package. Its two 8-bit quasi-bidirectional ports, P07–P00 and P17–P10, can be individually configured as inputs or outputs without a separate data-direction register. The device also includes an open-drain interrupt output and three hardware address inputs, allowing as many as eight devices to share an I2C bus. An I/O expander is an interface IC that extends the number of digital input and output lines available to a microcontroller or other host processor. The PCF8575 belongs to the I2C interface IC hierarchy and uses a serial command-and-data bus to transfer port state over two wires. Its 16 quasi-bidirectional lines can reduce the number of GPIO pins required by a host while remaining suitable for common logic-level inputs, relay-control signals, status indicators, and LED loads. Each quasi-bidirectional I/O has latched output capability and high-current drive for directly driving LEDs. The same line can be read as an input without changing the output latch, although the electrical behavior differs from a conventional push-pull output. At power-on, all I/O ports are high. The three address pins provide hardware-selectable device addresses for a maximum of eight PCF8575 devices on one bus, while the open-drain interrupt output provides a hardware indication of input-port state changes. The interface supports both I2C and SMBus operation, and the verified product information identifies operation up to 400 kHz. Low standby-current consumption is specified at a maximum of 10 µA. These characteristics make the device useful in embedded systems where bus wiring, connector pin count, standby power, or host GPIO availability constrain the design. The 24-pin SSOP, identified by distributor records as SSOP-24 with a 5.30 mm width and 0.209 inch lead spacing, supports compact surface-mount assembly. Typical uses include reading switches and keypads, driving LED indicators, monitoring digital control signals, controlling discrete transistors or relays, and expanding I/O in industrial controllers, appliance controllers, test equipment, and microcontroller boards. Because the interrupt output is open-drain, multiple interrupt-capable devices can share a common signal when the system supports wired-AND behavior. Firmware must also account for the I2C address, port polarity, and quasi-bidirectional input current requirements. The primary design consideration is choosing the pull-up voltage and ensuring that the bus capacitance and wiring permit reliable operation at 400 kHz. I2C pull-up resistors should be placed on the host side of long or branched wiring, and software should acknowledge only the interrupt source determined by the device address. The available verified material does not provide a complete pin table, explicit price values, or detailed absolute-maximum ratings. This product page consolidates the verified manufacturer description, distributor package identification, I2C features, interrupt behavior, power-on state, and available substitute references. It also adds application guidance, engineering caveats, and a transparent distinction between verified specifications and parameters that still require confirmation from the complete manufacturer datasheet.
PCF8575DW - 16-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCF8575DW is a 16-bit I2C/SMBus remote I/O expander with interrupt output, designed for 2.5 V to 5.5 V operation and packaged in a 24-pin SOIC. It provides 16 general-purpose digital I/O lines through a two-wire serial interface, making it useful for expanding microcontroller pin availability in embedded control systems. The device supports a 400 kHz fast I2C bus and includes three hardware address pins for addressing up to eight devices on the same bus. An I/O expander is an interface IC that translates serial bus commands into parallel digital input or output lines. The PCF8575 belongs to the I2C I/O expander category, within interface ICs and broader semiconductor power and signal-conditioning systems. Its design allows a host microcontroller to control or monitor multiple discrete digital signals while conserving the limited I/O pins available on small microcontrollers. Key features include 16 I/O lines, an operating supply range of 2.5 V to 5.5 V, a maximum I2C clock frequency of 400 kHz, low standby-current consumption of 10 uA maximum, and an open-drain interrupt output. The outputs are latched and can provide high-current drive capability for directly driving LEDs. A current source connected to VCC also allows outputs to be actively driven high for systems that require an active-high output state. The PCF8575DW communicates through SCL and SDA, with three address pins selecting one of eight possible bus addresses. The interrupt output provides a hardware indication that an input state has changed, allowing the host controller to respond without continuously polling the expander. The 400 kHz bus rate supports efficient transfers between the controller and the expanded I/O bank, while the 2.5 V to 5.5 V supply range supports both 3.3 V and 5 V systems. Typical applications include industrial control panels, keypad and button interfaces, LED status indicators, relay or transistor control, sensor and switch monitoring, and general-purpose embedded system I/O expansion. The PCF8575DW is particularly suitable when a controller has insufficient GPIO pins for external switches, indicators, or actuators. Its interrupt output can reduce host processing time when multiple remote inputs require attention. When designing around the PCF8575DW, confirm the controller's I2C voltage, pull-up resistor arrangement, address selection, and the electrical requirements of every connected load. The open-drain interrupt output requires appropriate pull-up treatment, and LED or relay loads must remain within the device's stated drive and current limits. The 24-pin SOIC footprint is intended for surface-mount PCB assembly. This product page combines the verified manufacturer and distributor descriptions, packaging information, source links, and engineering-oriented design guidance for engineers evaluating the PCF8575DW. It distinguishes verified facts from unavailable detailed specifications and provides practical context for choosing a 16-bit I2C/SMBus I/O expander in embedded control designs.
PCF8575DWR - 16-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCF8575DWR is a 16-bit I2C and SMBus I/O expander with interrupt, operating from 2.5 V to 5.5 V in a 24-pin SOIC (DW) package. It adds 16 latched quasi-bidirectional I/O lines to a host microcontroller through a two-wire serial bus, supports operation up to 400 kHz, and provides three hardware address pins for connecting up to eight devices on one bus. The device also includes an open-drain interrupt output for change notification. An I/O expander is an interface IC that converts serial commands from a microcontroller into parallel input or output signals. In the product hierarchy, the PCF8575 belongs to the I2C GPIO expander class, within interface ICs and broader digital semiconductor systems. It is useful when a controller needs more GPIO pins than are available directly, avoiding a redesign or the addition of a larger microcontroller package. Key features include 16 independently latched I/O ports, a 2.5 V to 5.5 V supply range, 400 kHz fast I2C operation, and low standby-current consumption of 10 uA maximum. Three hardware address pins provide eight selectable bus addresses. The outputs can latch data for direct LED drive and include a current source to VCC for actively driving a high. An open-drain interrupt output allows a controller to react to selected input changes without continuously polling the device. The PCF8575 implements a simple register-based interface in which the 16 ports are used for data transfer, configuration, and output control. Its quasi-bidirectional I/O structure suits many microcontroller systems, although each pin is intended primarily for ordinary digital loads rather than unrestricted capacitive or high-current loads. Power and signal behavior remain compatible with the 2.5 V to 5.5 V operating range stated by Texas Instruments. Typical applications include industrial control modules, keypad and switch interfaces, LED status panels, relay or solenoid driver boards, building-automation equipment, and small embedded control systems. The device is particularly useful when a host controller needs 16 additional lines while retaining a compact 24-pin SOIC footprint and a two-wire connection to the main PCB. Designers should account for the quasi-bidirectional output architecture, use appropriate pull-up arrangements for open-drain interrupt signaling, and confirm that connected loads remain within the device's output-drive limits. I2C pull-up resistance and bus capacitance should be selected for the full system, including cable length, bus speed, and the number of devices. This page combines manufacturer specifications, distributor availability, package details, practical application guidance, and same-footprint replacement analysis to support faster component selection and PCB-level decision-making.
PCF8575PW - 16-Bit I2C I/O Expander | Texas Instruments
Texas Instruments PCF8575PW is a 16-bit I2C/SMBus I/O expander with interrupt output, operating from 2.5 V to 5.5 V and supporting bus speeds up to 400 kHz. The device is packaged in a 24-pin TSSOP (PW) package and provides three hardware address inputs for operating as many as eight devices on one bus. An I/O expander is an interface IC that converts a serial two-wire bus into additional parallel input and output lines. In the product hierarchy, the PCF8575 belongs to the I/O expander class, interface ICs, and integrated circuits. It allows a microcontroller with limited GPIO pins to control or monitor additional external signals without requiring a large number of direct host-controller pins. Key features include 16 individually controlled I/O lines, an open-drain interrupt output, and a maximum standby-current consumption of 10 µA. The three address pins allow up to eight PCF8575 devices to share an I2C bus. Outputs are latched and have high-current drive capability for directly driving LEDs, while a current source to VCC supports actively driving a high output state. The PCF8575 interface uses SCL and SDA for serial communication and provides an open-drain interrupt for signaling the host controller. Its 400 kHz fast-I2C capability suits embedded control systems operating at moderate bus rates. The device is compatible with most microcontrollers, making it useful where firmware and board space make another dedicated parallel interface impractical. Typical uses include LED panels, key scanners, relay or switch controls, sensor and switch inputs, and general-purpose remote I/O in industrial, consumer, communications, and embedded systems. Each of the 16 I/O ports can be configured as an input or output through the serial interface, while the interrupt output can reduce unnecessary host-controller polling. Designers should account for the open-drain nature of the interrupt and I2C bus, provide suitable pull-up resistors, confirm address configuration, and review the datasheet for power-on output states and current limits. External drivers may be required when a load exceeds the device's specified drive capability. This page consolidates verified manufacturer and distributor information, documents where detailed ratings are unavailable, and distinguishes true package-compatible alternatives from look-alike expanders whose register behavior differs. It also provides application-specific engineering guidance that helps engineers evaluate the PCF8575PW before committing it to an existing PCB.
PCF8575PWR - 16-Bit I2C I/O Expander | Texas Instruments
The Texas Instruments PCF8575PWR is a 16-bit I2C/SMBus I/O expander with an interrupt output, a 2.5 V to 5.5 V operating range, and a 400 kHz bus rate. The device is packaged in a 24-pin TSSOP and adds 16 quasi-bidirectional I/O lines to a host controller over a two-wire serial interface. An I/O expander is an interface IC that extends the number of digital input and output pins available to a microcontroller or other embedded controller. The PCF8575 sits between the host processor and external peripherals, using I2C or SMBus for command and data transfer while presenting a parallel port to connected circuitry. Its two independent eight-bit ports support both input and output operation without separate data-direction registers. The PCF8575PWR provides 16 quasi-bidirectional I/O lines, with each line usable as an input or output. Its latched outputs have high-current drive capability for directly driving LEDs. Three hardware address pins allow up to eight devices to share the same I2C bus, while the open-drain interrupt output provides a hardware indication of input-port activity. The interface supports operation up to 400 kHz, and standby current consumption is specified at no more than 10 microamperes. All I/O pins are high at power-on, which provides a defined reset state for the output latch. The quasi-bidirectional architecture includes a weak current source toward VCC, so engineers should account for this behavior when designing inputs, pull-ups, and output transitions. Typical uses include expanding a limited microcontroller pin count for LEDs, switches, keypads, sensors, relay-control logic, and simple digital display interfaces. Because the device communicates over I2C or SMBus, it is particularly useful when a design needs many slow-changing digital lines but cannot allocate a dedicated parallel port on the host controller. A key design consideration is the difference between quasi-bidirectional inputs and conventional push-pull outputs. Pull-up requirements, leakage currents, and the desired high or low state must be evaluated for every connected signal. Designers should also confirm address selection, interrupt handling, and supply levels before assigning functions to the two eight-bit ports. This product page organizes the manufacturer specifications, pin assignments, application guidance, and same-footprint alternatives into an engineering-focused reference. It also distinguishes direct pin-compatible choices from related expanders whose input or reset behavior differs, helping simplify design validation without obscuring the trade-offs that matter on the PCB.