NXP Semiconductors PCA9675PW,112

Overview

PCA9675PW,112 from NXP Semiconductors is a 16-bit remote I/O expander for Fast-mode Plus (Fm+) I²C-bus systems, providing quasi-bidirectional I/O ports with 25 mA sink per pin, 400 mA total package sink capacity, and active-low open-drain interrupt output. It operates from 2.3 V to 5.5 V, supports 1 MHz I²C-bus communication, and is used in LED signage, industrial PLCs, and server board management.

For engineers reviewing the PCA9675PW,112 datasheet, PCA9675PW,112 pinout, PCA9675PW,112 application, or PCA9675PW,112 equivalent, key selection criteria include its 1 MHz Fm+ compatibility, 64 programmable slave addresses, latched outputs for direct LED driving, and interrupt-driven input change detection without polling.

Technical Context

The PCA9675PW,112 implements a quasi-bidirectional I/O architecture where all 16 pins (P00–P07, P10–P17) default to high-impedance inputs at power-up and support both input and output modes without direction control lines. Its internal Power-On Reset (POR) and software reset via General Call address 00h ensure deterministic initialization.

It features an open-drain INT pin that asserts on any rising/falling edge of port inputs, enabling event-driven microcontroller wake-up. The device uses three address pins (AD0–AD2) to select one of 64 unique I²C slave addresses, eliminating bus conflicts in dense multi-device systems.

Key Specifications

Pinout & Package

TSSOP24 package (SOT355-1), 24-pin plastic thin shrink small outline, 4.4 mm body width, lead pitch 0.65 mm. Exposed pad not present; standard thermal dissipation via PCB copper.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar remote I/O expander applications.

Compared with PCA9674PW,112, the PCA9675PW,112 doubles I/O count and total sink capacity; compared with PCF8575CPW,118, it delivers 2.5× higher I²C bandwidth, 4× greater bus drive, and 4× more address options - critical for scalable, high-performance embedded I/O systems.

Availability

PCA9675PW,112 is available at Aetrix Electronics and suitable for LED signage, industrial PLCs, and server board management requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for PCA9675PW,112 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in interface and system-level ICs.

The PCA9675 belongs to NXP's Fast-mode Plus I²C remote I/O family, designed specifically to replace legacy expanders in high-density, high-speed embedded control systems demanding interrupt-driven responsiveness and scalable addressing.

FAQ

What is the maximum I²C clock frequency supported by the PCA9675PW,112?

The PCA9675PW,112 supports Fast-mode Plus (Fm+) I²C operation up to 1 MHz. This is confirmed in the NXP datasheet Rev. 2 (2011), Section 2 "Features and benefits", and enables faster configuration writes and real-time PWM dimming control compared to standard 400 kHz I²C devices. The PCA9675PW,112 maintains full electrical compliance at this rate with 30 mA SDA sink capability.

Does the PCA9675PW,112 require external pull-up resistors on SDA and SCL lines?

Yes, the PCA9675PW,112 requires external pull-up resistors on both SDA and SCL lines, as specified in Section 9 "Characteristics of the I²C-bus" of the datasheet. Its open-drain outputs rely on these resistors to establish HIGH logic levels; typical values range from 1.8 kΩ to 10 kΩ depending on bus capacitance and speed requirements. The PCA9675PW,112 does not integrate internal pull-ups.

How does the interrupt (INT) pin of the PCA9675PW,112 behave during I/O state changes?

The INT pin of the PCA9675PW,112 is an active-low open-drain output that asserts (goes LOW) on any rising or falling edge detected on any of its 16 I/O pins. As described in Section 8.5, the interrupt deasserts (returns HIGH) only after the corresponding port data is read or written - ensuring edge-triggered notification without spurious re-triggers. This behavior is intrinsic to the PCA9675PW,112's interrupt logic.

Can the PCA9675PW,112 drive LEDs directly without external transistors?

Yes, the PCA9675PW,112 can drive standard LEDs directly: each of its 16 quasi-bidirectional I/O pins supports 25 mA sink current, and the total package sink capacity is 400 mA. This is explicitly stated in Section 2 "Features and benefits" and validated in the functional description. The PCA9675PW,112's latched outputs maintain stable states during microcontroller communication, making it suitable for direct LED segment control.

What is the purpose of the Device ID register in the PCA9675PW,112?

The Device ID register in the PCA9675PW,112 is a 24-bit read-only field containing manufacturer ID (8 bits), part identification (13 bits), and die revision (3 bits). Accessed via reserved I²C address 0xF4 (1111 100x), it enables firmware-level device verification and BOM traceability. This feature is documented in Section 7.2.2 and is implemented in silicon for the PCA9675PW,112.