NXP Semiconductors PCA9670PW,112

Overview

The PCA9670PW,112 from NXP Semiconductors is an 8-bit remote I/O expander IC for Fast-mode Plus (Fm+) I²C-bus systems, operating from 2.3 V to 5.5 V with 5.5 V-tolerant I/Os. It provides eight quasi-bidirectional ports, 1 MHz I²C interface with 30 mA SDA sink drive, active-low hardware reset, and supports up to 64 devices on one bus for scalable I/O expansion in LED control and keypad monitoring.

For engineers reviewing the PCA9670PW,112 datasheet, PCA9670PW,112 pinout, PCA9670PW,112 application, or PCA9670PW,112 equivalent, key selection criteria include its Fm+ I²C compatibility, 25 mA per-port sink capability for direct LED driving, latch-up immunity (>100 mA), and TSSOP16 package suitability for space-constrained industrial and mobile designs.

Technical Context

The PCA9670PW,112 implements a quasi-bidirectional I/O architecture with no direction register-each port defaults to input at power-up with a 100 µA weak pull-up, and can be independently used as input (monitoring interrupts/keypads) or output (driving LEDs) via a single 8-bit register. Its internal Power-On Reset and active-low RESET pin initialize all I/Os to high-impedance inputs.

It supports Fast-mode Plus I²C (1 MHz) with 30 mA SDA sink strength enabling operation on buses up to 4000 pF without buffers, and features software reset via General Call address 00h + data byte 06h, plus read-only 24-bit Device ID (manufacturer, part ID, revision) accessible at reserved address F8h/F9h.

Key Specifications

Pinout & Package

PCA9670PW,112 is housed in a 16-pin TSSOP package (SOT403-1), 4.4 mm body width, lead pitch 0.65 mm, with exposed pad not present (unlike HVQFN variant). Pinout matches SO16 and TSSOP16 footprints per NXP documentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9671PW,112, the PCA9670PW,112 omits the dedicated INT pin-reducing cost and complexity where polled I/O suffices. Against TCA6408APWR, it provides superior bus configurability via three address pins and software-initiated reset, enhancing scalability and fault resilience in multi-device systems.

Availability

PCA9670PW,112 is available at Aetrix Electronics and suitable for industrial control panels, LED signage systems, and medical device user interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PCA9670PW,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 company specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with leadership in I²C, CAN, and NFC technologies.

The PCA9670PW,112 belongs to NXP's remote I/O expander product line, designed specifically to simplify I²C-based peripheral expansion in resource-constrained embedded systems while maintaining industrial-grade reliability and thermal performance.

FAQ

What is the maximum I²C bus speed supported by the PCA9670PW,112?

The PCA9670PW,112 supports Fast-mode Plus (Fm+) I²C operation up to 1 MHz. This enables high-speed communication for time-sensitive applications such as LED PWM dimming and rapid I/O state updates. The 30 mA SDA sink capability ensures reliable signal integrity even on heavily loaded buses up to 4000 pF, eliminating the need for external bus buffers in most implementations of the PCA9670PW,112.

Does the PCA9670PW,112 require external pull-up resistors on its I²C lines?

Yes, the PCA9670PW,112 requires external pull-up resistors on both SCL and SDA lines, as specified in the I²C bus standard. The device does not integrate internal pull-ups on these lines. Resistor values depend on bus capacitance and desired rise time; typical values range from 1.8 kΩ to 10 kΩ for 3.3 V or 5 V systems. The PCA9670PW,112's 30 mA SDA sink strength allows use of lower-value resistors for faster edges on high-capacitance buses.

How does the quasi-bidirectional I/O architecture of the PCA9670PW,112 differ from standard GPIO expanders?

The PCA9670PW,112 uses a quasi-bidirectional architecture with no direction register-each port defaults to input with a 100 µA weak pull-up and can be driven low via internal transistor. Writing '1' configures it as input or high-impedance output; writing '0' actively pulls low. This simplifies firmware, reduces memory overhead, and enables dynamic reconfiguration per port-unlike traditional expanders requiring explicit direction register writes before data transfer in the PCA9670PW,112.

Can the PCA9670PW,112 drive LEDs directly without external components?

Yes, the PCA9670PW,112 can drive standard LEDs directly using its 25 mA per-port sink capability. Connect the LED anode to VDD through a current-limiting resistor and cathode to a PCA9670PW,112 I/O pin (e.g., P0–P7). When the pin is written '0', it sinks up to 25 mA, lighting the LED. Total package sink is limited to 200 mA, so simultaneous activation of more than eight 25 mA LEDs is not permitted in the PCA9670PW,112.

What is the purpose of the RESET pin on the PCA9670PW,112, and how should it be used?

The RESET pin on the PCA9670PW,112 is an active-low asynchronous input that forces all I/Os and registers to their power-up default state (inputs with 100 µA pull-up) when held low for ≥tw(rst). It must be pulled up to VDD via an external resistor (e.g., 10 kΩ) if not actively driven. This pin enables deterministic recovery from brown-out or communication errors independent of the I²C bus state, ensuring safe initialization of the PCA9670PW,112 in mission-critical systems.