NXP Semiconductors PCA9675DK,118

Overview

PCA9675DK,118 from NXP Semiconductors is a 16-bit quasi-bidirectional I/O expander 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 delivers 25 mA sink per I/O pin, 400 mA total package sink capacity, and supports 1 MHz I²C-bus communication-enabling LED PWM dimming in signage and industrial control interfaces.

For engineers reviewing the PCA9675DK,118 datasheet, PCA9675DK,118 pinout, PCA9675DK,118 application, or PCA9675DK,118 equivalent, key selection considerations include its 24-pin SSOP package with 0.635 mm pitch, active-low open-drain interrupt output, 64 programmable slave addresses, and latched outputs for direct LED drive without external buffers.

Technical Context

The PCA9675DK,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 independent input/output configuration via I²C writes. Its internal Power-On Reset (POR) and software reset (via General Call address 00h + data 06h) ensure deterministic initialization.

It features an active-low open-drain INT output that asserts on any rising or falling edge of port inputs, enabling asynchronous event notification to the host microcontroller without polling. The device supports readable Device ID (24-bit manufacturer/part/revision field) and uses AD0–AD2 pins to select among 64 I²C slave addresses (20h–EEh), avoiding bus conflicts in multi-device systems.

Key Specifications

Pinout & Package

PCA9675DK,118 is supplied in a 24-lead plastic shrink small outline package (SSOP24) with 3.9 mm body width and 0.635 mm lead pitch (SOT556-1). The exposed pad is not present - thermal management relies on PCB copper area under the package body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9674DK,118, the PCA9675DK,118 doubles I/O count and address space while maintaining pin compatibility; versus PCF8575CD,118, it delivers 2.5× bus speed, 4× sink capacity, and enhanced diagnostics - justifying upgrade in performance-critical or scalable designs.

Availability

PCA9675DK,118 is available at Aetrix Electronics and suitable for LED signage, industrial PLCs, and server board management requiring stable component supply, long-term manufacturability, and guaranteed I²C-bus interoperability.

Supply support for PCA9675DK,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 focused on secure connectivity solutions for automotive, industrial, and IoT applications.

The PCA9675DK,118 belongs to NXP's Fast-mode Plus I²C I/O expander product line, engineered specifically for high-density, high-speed remote GPIO expansion in noise-immune industrial and commercial control systems.

FAQ

What is the maximum I²C-bus speed supported by the PCA9675DK,118?

The PCA9675DK,118 supports Fast-mode Plus (Fm+) I²C operation up to 1 MHz - a 2.5× improvement over standard Fast-mode (400 kHz). This higher speed enables faster polling of I/O states and smoother PWM-based LED dimming control. The PCA9675DK,118 maintains full backward compatibility with Standard-mode (100 kHz) and Fast-mode (400 kHz) I²C controllers, ensuring integration flexibility across diverse host platforms.

Does the PCA9675DK,118 require external pull-up resistors on SDA and SCL lines?

Yes, the PCA9675DK,118 requires external pull-up resistors on both SDA and SCL lines, as mandated by the I²C specification. Its SDA pin supports up to 30 mA sink current, allowing reliable operation on buses with up to 4000 pF capacitance. The PCA9675DK,118 does not include internal pull-ups on these lines, so proper resistor sizing (typically 1–10 kΩ depending on bus speed and capacitance) is essential for signal integrity and timing compliance.

How does the interrupt (INT) pin of the PCA9675DK,118 behave during I/O state changes?

The INT pin of the PCA9675DK,118 is an active-low open-drain output that asserts (goes LOW) on any rising or falling edge detected on any of its 16 I/O pins. The interrupt remains asserted until the host reads the affected port register or writes new data to it - at which point the INT line is de-asserted (returns HIGH). This behavior allows the PCA9675DK,118 to offload continuous polling from the MCU and respond immediately to external events like button presses or sensor triggers.

Can the PCA9675DK,118 directly drive standard LEDs without additional components?

Yes, the PCA9675DK,118 can directly drive standard 20 mA LEDs using its quasi-bidirectional I/O pins, each rated for 25 mA sink current. When configured as outputs, pins P00–P07 and P10–P17 provide latched logic levels and sufficient current to illuminate common anode LED segments. The PCA9675DK,118's 400 mA total package sink capacity allows all 16 pins to drive LEDs simultaneously at full brightness - eliminating the need for external transistor arrays or LED driver ICs in many lighting applications.

What package type is used for the PCA9675DK,118 and how does it differ from PCA9675D or PCA9675DB?

The PCA9675DK,118 uses a 24-lead SSOP package with 3.9 mm body width and 0.635 mm lead pitch (SOT556-1), distinct from the wider 7.5 mm SO24 (PCA9675D) and 5.3 mm SSOP24 (PCA9675DB). While pinout and functionality are identical across these variants, the PCA9675DK,118's compact footprint saves PCB area in space-constrained applications like server modules or portable gaming hardware. All share the same electrical specifications and software interface - only mechanical dimensions and thermal characteristics differ.