NXP Semiconductors PCA9675DB,112

Overview

The PCA9675DB,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 1 MHz I²C-bus operation. It integrates an active-low open-drain interrupt output (INT), 64 programmable slave addresses via AD0–AD2, and operates from 2.3 V to 5.5 V with 5.5 V-tolerant I/Os-enabling direct LED PWM dimming and high-density bus expansion in industrial control panels.

For engineers reviewing the PCA9675DB,112 datasheet, PCA9675DB,112 pinout, PCA9675DB,112 application, or PCA9675DB,112 equivalent, key selection criteria include its Fm+ I²C speed advantage over PCF8575, latched output architecture for stable LED drive, interrupt-driven port change detection, and compatibility with SO24, TSSOP24, HVQFN24, and DHVQFN24 packages.

Technical Context

The PCA9675DB,112 implements a quasi-bidirectional I/O architecture where all 16 pins (P00–P07, P10–P17) default to inputs at power-up and support independent input/output configuration without direction-control lines. Its internal Power-On Reset (POR) and software reset (via General Call address 00h + data byte 06h) ensure deterministic initialization.

It features an interrupt logic block that asserts INT on any rising or falling edge of input port states, with automatic deactivation upon read/write access to the triggering port. The device supports Device ID read (manufacturer, part ID, revision) using reserved address 1111100Xb, enabling firmware-level device identification and version validation.

Key Specifications

Pinout & Package

PCA9675DB,112 is supplied in SO24 package (SOT137-1), a plastic small outline package with 24 leads and 7.5 mm body width. Pin numbering follows standard SOIC layout with pin 1 at top-left corner (index mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9674DB,112, the PCA9675DB,112 doubles I/O count without increasing package size or power; versus PCF8575T/3,118, it delivers 2.5× faster bus throughput, 10× higher SDA drive, and 4× greater total sink capacity-making it essential for modern high-density, real-time I/O systems.

Availability

PCA9675DB,112 is available at Aetrix Electronics and suitable for industrial PLCs, LED signage controllers, server management units, and gaming peripheral interfaces requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.

Supply support for PCA9675DB,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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in I²C interface IP and robust mixed-signal design.

The PCA9675DB,112 belongs to NXP's Fast-mode Plus I²C I/O expander product line, engineered specifically for high-reliability industrial control, LED lighting, and embedded systems demanding deterministic interrupt response and scalable bus architecture.

FAQ

What is the maximum I²C-bus speed supported by the PCA9675DB,112?

The PCA9675DB,112 supports Fast-mode Plus (Fm+) I²C operation up to 1 MHz. This is confirmed in the NXP datasheet Rev. 2 (October 2011), Section 2 "Features and benefits". The 1 MHz capability enables faster I/O updates and higher-resolution LED PWM dimming compared to standard 400 kHz Fast-mode devices like the PCF8575. The PCA9675DB,112 maintains full electrical compliance-including SDA sink strength (30 mA) and noise filtering-at this speed.

How many I/O pins does the PCA9675DB,112 provide, and what is their default state at power-up?

The PCA9675DB,112 provides 16 quasi-bidirectional I/O pins: P00–P07 and P10–P17. Per Section 8.1 of the datasheet, all I/Os default to HIGH at power-up due to internal Power-On Reset (POR) initialization. This ensures safe input mode operation immediately after power application, preventing unintended current flow or bus contention before firmware configures directionality. The PCA9675DB,112 retains this behavior regardless of supply voltage within its 2.3 V–5.5 V range.

Does the PCA9675DB,112 support interrupt-driven I/O change detection?

Yes, the PCA9675DB,112 features an active-low open-drain interrupt output (INT) that asserts on any rising or falling edge of input port states (Section 8.5). The interrupt is automatically cleared when the corresponding port register is read or written, enabling precise event capture without polling. This functionality is fully implemented in the PCA9675DB,112's silicon and requires only an external pull-up resistor on the INT line for MCU interfacing.

What package type is used for the PCA9675DB,112, and how does it differ from other PCA9675 variants?

The PCA9675DB,112 uses the SO24 package (SOT137-1), a plastic small outline package with 24 leads and 7.5 mm body width. This matches the PCA9675D variant listed in Table 1 of the datasheet. Unlike PCA9675PW (TSSOP24), PCA9675BQ (DHVQFN24), or PCA9675BS (HVQFN24), the PCA9675DB,112 is not pin-compatible with those QFN or thin-shrink packages-differences in lead pitch, thermal pad presence, and mechanical dimensions require separate PCB layouts.

Can the PCA9675DB,112 directly drive LEDs, and what is its per-pin and total sink capability?

Yes, the PCA9675DB,112 is designed for direct LED drive: each of its 16 I/O pins supports 25 mA sink current, and the entire device sustains 400 mA total package sink capacity (Section 2). This allows simultaneous illumination of all 16 LEDs at full brightness without external transistors. The PCA9675DB,112 achieves this via latched outputs and optimized output stage design-verified in the datasheet's Absolute Maximum Ratings and DC Characteristics tables.