NXP Semiconductors PCA9671DB,118

Overview

PCA9671DB,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, 400 mA total package sink capacity, and 1 MHz I²C-bus operation. It replaces the PCF8575 with higher drive strength, faster bus speed, and an active-low RESET input instead of interrupt output-enabling LED PWM dimming and dense multi-device bus topologies in industrial control panels.

For engineers reviewing the PCA9671DB,118 datasheet, PCA9671DB,118 pinout, PCA9671DB,118 application, or PCA9671DB,118 equivalent, key selection criteria include its 1 MHz Fm+ I²C interface, 2.3–5.5 V supply range with 5.5 V-tolerant I/Os, 64 programmable slave addresses, latched outputs, and hardware/software reset capability-critical for reliable I/O expansion in space-constrained embedded systems.

Technical Context

The PCA9671DB,118 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 direct LED driving via 25 mA sink capability per pin. Its internal Power-On Reset (POR) and dedicated active-low RESET pin ensure deterministic initialization independent of I²C-bus state.

It operates as an I²C-bus slave with Fast-mode Plus compliance (1 MHz), 30 mA SDA sink drive for 4000 pF buses, and supports software reset via General Call address (00h) + data byte 06h. Device ID read (manufacturer, part ID, revision) is accessible via reserved address F4h (1111 100x).

Key Specifications

Pinout & Package

PCA9671DB,118 is packaged in SO24 (SOT137-1), with 24-pin plastic small outline, 7.5 mm body width. Pin functions are identical across SO24, TSSOP24, HVQFN24, and DHVQFN24 variants per NXP datasheet Rev. 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCF8575CD,118, PCA9671DB,118 delivers 2.5× faster I²C throughput and 4× higher drive strength; versus PCA9673BS,118, it trades interrupt capability for simplified pinout and lower cost where polling suffices.

Availability

PCA9671DB,118 is available at Aetrix Electronics and suitable for industrial control panels, medical instrumentation, and server management subsystems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for PCA9671DB,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 PCA9671DB,118 belongs to NXP's Fast-mode Plus I²C I/O expander product line, designed specifically to replace legacy expanders in high-density, high-speed embedded systems where bus loading, timing precision, and reliability are critical.

FAQ

What is the maximum I²C-bus clock frequency supported by the PCA9671DB,118?

The PCA9671DB,118 supports Fast-mode Plus (Fm+) I²C-bus operation up to 1 MHz. This is confirmed in the NXP datasheet Rev. 3 Section 2 (Features and benefits) and Section 9. The 1 MHz capability enables time-critical applications such as LED PWM dimming and fast sensor polling without bus congestion. Standard-mode (100 kHz) and Fast-mode (400 kHz) are also fully supported.

Does the PCA9671DB,118 have an interrupt output like the PCF8575?

No, the PCA9671DB,118 does not include an interrupt output. As stated in the General Description section, the interrupt output on the PCF8575 is replaced by an active-low RESET input on the PCA9671DB,118. Input changes must be monitored via periodic register reads. For designs requiring interrupt capability, NXP recommends the PCA9673BS,118 - a pin-compatible variant that retains RESET and adds INT.

How many I²C slave addresses does the PCA9671DB,118 support, and how are they configured?

The PCA9671DB,118 supports 64 unique I²C slave addresses, configured using three address pins: AD0, AD1, and AD2. These pins accept static HIGH/LOW logic levels (no internal pull-ups), selecting addresses from 20h to BEh in hexadecimal. Reserved addresses (General Call 00h and Device ID F4h) are excluded from normal operation per datasheet Table 3.

Can the PCA9671DB,118 directly drive LEDs, and what is its per-pin current limit?

Yes, the PCA9671DB,118 can directly drive LEDs with a guaranteed sink current of 25 mA per I/O pin (P00–P07, P10–P17). Its total package sink capacity is 400 mA, allowing all 16 pins to operate simultaneously at full 25 mA. This eliminates external driver transistors in most indicator and display applications, as verified in Section 2 (Features and benefits) and Section 10.1 of the datasheet.

What reset mechanisms does the PCA9671DB,118 provide, and how do they differ?

The PCA9671DB,118 provides three reset mechanisms: (1) Internal Power-On Reset (POR) triggered at VDD ≥ VPOR, (2) Hardware RESET via active-low pin (minimum pulse width tw(rst)), and (3) Software Reset via I²C General Call address (00h) followed by data byte 06h. All three initialize I/Os as inputs and restore default register states, as detailed in Sections 8.4, 8.5, and 7.2.1 of the datasheet.