NXP Semiconductors PCA9673D,118

Overview

PCA9673D,118 from NXP Semiconductors is a 16-bit remote I/O expander for Fast-mode Plus (Fm+) I²C-bus systems, providing quasi-bidirectional GPIO with 25 mA sink per pin, active-low open-drain interrupt (INT), and hardware RESET input. It operates from 2.3 V to 5.5 V, supports 1 MHz I²C-bus communication, and delivers 400 mA total package sink capacity-enabling direct LED driving in signage and industrial control panels.

For engineers reviewing the PCA9673D,118 datasheet, PCA9673D,118 pinout, PCA9673D,118 application, or PCA9673D,118 equivalent, key selection criteria include its 1 MHz Fm+ I²C interface, 16 programmable slave addresses, latched output architecture, interrupt-driven event notification, and SO24 package compatibility with legacy PCF8575 layouts (with RESET replacing A2).

Technical Context

The PCA9673D,118 implements a dual-octet quasi-bidirectional I/O architecture (P00–P07 and P10–P17), where each port defaults to HIGH at power-up and functions as input or output without direction control. Its I²C interface complies with Standard- and Fast-mode specifications and extends to 1 MHz Fast-mode Plus, enabling PWM dimming support and higher bus node count via 30 mA SDA sink capability.

Internal Power-On Reset (POR), dedicated active-low RESET pin, and software-initiated reset (via General Call 00h + 06h) ensure deterministic initialization. The INT pin asserts on any port edge change and clears automatically upon read/write access to the triggering port register or on rising edge of write pulse-enabling efficient polling-free status monitoring in real-time embedded systems.

Key Specifications

Pinout & Package

PCA9673D,118 is supplied in SO24 (SOT137-1) plastic small outline package: 24-pin, 7.5 mm body width, surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCF8575CD, PCA9673D,118 delivers 2.5× faster I²C, 10× higher SDA drive, and 4× greater sink capacity-making it essential for LED dimming and high-node-count systems. Versus PCA9674D,118, it trades per-port configurability for lower gate count and reduced firmware overhead in fixed-function I/O roles.

Availability

PCA9673D,118 is available at Aetrix Electronics and suitable for LED signage, server management, industrial control, and PLC I/O expansion requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for PCA9673D,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 deep expertise in I²C ecosystem components and embedded interface IP.

The PCA9673D,118 belongs to NXP's Fast-mode Plus I²C remote I/O family, engineered specifically to replace legacy expanders in high-density, high-speed embedded control systems while maintaining pin-compatible upgrade paths.

FAQ

What is the maximum I²C-bus speed supported by the PCA9673D,118?

The PCA9673D,118 supports Fast-mode Plus (Fm+) I²C operation up to 1 MHz. This is double the 400 kHz limit of standard Fast-mode devices like the PCF8575 and enables faster I/O updates, real-time LED PWM dimming, and higher node counts on a single bus without repeaters or buffers. The 30 mA SDA sink capability ensures signal integrity even on 4000 pF bus loads.

How does the RESET pin on the PCA9673D,118 differ from the PCF8575?

The PCA9673D,118 replaces the PCF8575's A2 address pin with an active-low RESET input. This allows hardware-initiated reinitialization of all I/Os and registers to power-up defaults independent of I²C bus activity-critical for fail-safe recovery in industrial systems. Unlike the PCF8575, the PCA9673D,118 retains 16 address options using only AD0 and AD1, preserving bus scalability.

Can the PCA9673D,118 drive LEDs directly, and what is its total current capability?

Yes, the PCA9673D,118 can drive LEDs directly with 25 mA sink capability per I/O pin across all 16 ports. Its total package sink capacity is 400 mA, allowing all outputs to operate simultaneously at full rated current-ideal for LED signage, status indicators, and backlight control. Thermal design in the SO24 package supports this full load under typical industrial ambient conditions.

What happens to the I/O pins during power-up or reset on the PCA9673D,118?

Upon power-up or assertion of the RESET pin, the PCA9673D,118 initializes all 16 I/O pins (P00–P07, P10–P17) as HIGH-impedance inputs with internal weak pull-ups active. This safe default state prevents bus contention and unintended actuation. The internal Power-On Reset (POR) circuit holds the device in reset until VDD exceeds VPOR (~1.8 V), ensuring reliable initialization across the 2.3–5.5 V operating range.

Does the PCA9673D,118 support interrupt-driven I/O monitoring, and how is it implemented?

Yes, the PCA9673D,118 features an active-low open-drain INT pin that asserts on any rising or falling edge detected at any of its 16 I/O ports. The interrupt clears automatically upon reading the affected port register or writing new data to it-eliminating the need for explicit deassert commands. This enables efficient event-driven firmware architectures where the host MCU responds only when I/O state changes occur.