NXP Semiconductors PCA9673BS,118

Overview

PCA9673BS,118 from NXP Semiconductors is a 16-bit remote I/O expander with Fast-mode Plus (Fm+) I²C-bus interface (1 MHz), active-low open-drain interrupt (INT), hardware RESET input, and 25 mA per-pin sink capability for direct LED driving. It operates from 2.3 V to 5.5 V with 5.5 V tolerant I/Os and supports 16 programmable slave addresses via AD0/AD1 pins.

For engineers reviewing the PCA9673BS,118 datasheet, PCA9673BS,118 pinout, PCA9673BS,118 application, or PCA9673BS,118 equivalent, key selection considerations include its 400 mA total package sink capacity, quasi-bidirectional port architecture, Power-On Reset (POR) and software reset support, and HVQFN24 thermal-enhanced packaging for space-constrained industrial and embedded designs.

Technical Context

The PCA9673BS,118 implements a 16-bit quasi-bidirectional I/O port (P00–P07 and P10–P17), where each pin defaults to HIGH at power-up and functions as either input or output without direction control signals. Its Fm+ I²C interface supports 1 MHz operation with 30 mA SDA sink drive, enabling robust bus loading up to 4000 pF without buffers.

Interrupt generation is edge-triggered on any I/O state change, latched until cleared by read/write access or hardware RESET. The device integrates internal POR, external active-low RESET pin (pin 24 in HVQFN24), and software reset via General Call address (00h) + data byte 06h - all initializing I/Os to high-impedance inputs.

Key Specifications

Pinout & Package

HVQFN24 package (SOT616-1): 4 mm × 4 mm × 0.85 mm body, 24-terminal no-lead thermal-enhanced quad flat package with exposed thermal pad requiring PCB soldering for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9672BS,118 and TCA6408APWR, the PCA9673BS,118 uniquely combines 16-bit I/O, hardware RESET, 1 MHz Fm+, and 400 mA sink in an HVQFN24 package - making it the only option meeting concurrent requirements for high-density LED control, industrial reset robustness, and thermal-constrained layouts.

Availability

PCA9673BS,118 is available at Aetrix Electronics and suitable for LED signage, industrial PLCs, and medical equipment requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for PCA9673BS,118 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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with core expertise in interface, power management, and microcontroller technologies.

The PCA9673BS,118 belongs to NXP's Fast-mode Plus I²C I/O expander product line, designed specifically for high-speed, high-drive remote GPIO expansion in space- and reliability-constrained embedded systems.

FAQ

What is the function of the RESET pin on the PCA9673BS,118?

The RESET pin on the PCA9673BS,118 is an active-low hardware reset input that forces all I/Os and internal registers to their power-up default state (quasi-bidirectional inputs) when held LOW for ≥tw(rst). This provides deterministic recovery independent of I²C bus health - a key distinction from the PCF8575, which lacks this pin. The PCA9673BS,118 uses RESET in place of the A2 address pin found on legacy expanders.

Can the PCA9673BS,118 drive LEDs directly without external transistors?

Yes, the PCA9673BS,118 can drive standard LEDs directly: each of its 16 I/O pins supports 25 mA sink current, and the total package sink capacity is 400 mA. This allows simultaneous activation of all outputs at rated current - sufficient for indicator LEDs, 7-segment displays, or low-power LED matrices. The PCA9673BS,118's quasi-bidirectional architecture latches output states, ensuring stable illumination without continuous host refresh.

How does the interrupt (INT) pin on the PCA9673BS,118 operate?

The INT pin on the PCA9673BS,118 is an active-low open-drain output that asserts whenever any of the 16 I/O pins transitions (rising or falling edge). It remains asserted until cleared by reading the port register, writing to the port, or applying hardware RESET. This asynchronous notification eliminates the need for periodic I²C polling - reducing host MCU overhead and power consumption. The PCA9673BS,118's INT behavior is fully documented in Section 8.5 of its datasheet.

What package type is used for the PCA9673BS,118 and why does it matter?

The PCA9673BS,118 uses the HVQFN24 package (SOT616-1): a 4 mm × 4 mm × 0.85 mm thermal-enhanced quad flat no-lead package with an exposed center pad. This package delivers superior thermal dissipation versus SO24 or TSSOP24 - critical when sinking up to 400 mA total current. The exposed pad must be soldered to a PCB thermal pad with vias for reliable operation in industrial or high-ambient environments. This distinguishes the PCA9673BS,118 from pin-compatible variants like PCA9673D (SO24).

Does the PCA9673BS,118 support software reset, and how is it triggered?

Yes, the PCA9673BS,118 supports software reset via I²C General Call address (00h) followed by data byte 06h. Upon receiving this exact sequence, the device resets all registers and I/Os to power-up defaults without requiring hardware RESET assertion. This enables remote recovery during firmware updates or bus error conditions. The PCA9673BS,118 only acknowledges the 06h byte - any other value aborts the sequence. Full timing and protocol details are specified in Section 7.2.1 of the datasheet.