NXP Semiconductors PCA8575DK,118

Overview

PCA8575DK,118 from NXP Semiconductors is a 16-bit remote I/O expander for I²C-bus with interrupt, operating from 2.3 V to 5.5 V, featuring 25 mA sink per I/O pin, active LOW open-drain INT output, and 8 programmable slave addresses via AD0–AD2 pins. It enables microcontroller GPIO expansion in space-constrained industrial control and LED display systems.

For engineers reviewing the PCA8575DK,118 datasheet, PCA8575DK,118 pinout, PCA8575DK,118 application, or PCA8575DK,118 equivalent, key selection considerations include its SSOP24 package (3.9 mm body width, 0.635 mm pitch), quasi-bidirectional I/O architecture with power-on reset to inputs, and interrupt-driven port change detection without polling the I²C bus.

Technical Context

The PCA8575DK,118 implements a two-byte I²C register map where P00–P07 are written/read in the first byte and P10–P17 in the second, with interrupt cleared byte-wise upon reading each port register. Its internal Power-On Reset initializes all 16 I/Os as HIGH-impedance inputs with weak pull-ups.

It supports Fast-mode I²C at up to 400 kHz, uses no internal address-pin pull-ups (requiring external biasing of AD0–AD2), and features input filters suppressing <50 ns noise spikes on SDA/SCL. The INT line asserts on any rising or falling edge at any I/O pin and deasserts only after corresponding port data is read or written.

Key Specifications

Pinout & Package

PCA8575DK,118 is housed in a plastic shrink small outline package (SSOP24) with 24 leads, 3.9 mm body width, and 0.635 mm lead pitch (SOT556-1). This compact surface-mount package supports high-density PCB layouts in industrial and telecom equipment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9555PW,118 and PCF8575T/3,118, the PCA8575DK,118 provides faster, byte-granular interrupt clearing and higher sink current per pin (25 mA vs. 20 mA), making it optimal for LED-dense or time-critical industrial interfaces where deterministic response to individual port changes is essential.

Availability

PCA8575DK,118 is available at Aetrix Electronics and suitable for industrial control, medical equipment panels, and LED signage requiring stable component supply and long-term manufacturing support.

Supply support for PCA8575DK,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 peripherals and mixed-signal interface ICs.

The PCA8575DK,118 belongs to NXP's remote I/O expander product line, designed specifically for cost-sensitive, space-constrained embedded systems needing reliable GPIO extension with minimal software overhead and robust interrupt handling.

FAQ

What is the package type and pin count of the PCA8575DK,118?

The PCA8575DK,118 uses a plastic shrink small outline package (SSOP24) with 24 leads, 3.9 mm body width, and 0.635 mm lead pitch (SOT556-1). This compact footprint supports high-density PCB layouts while maintaining hand-solderability and compatibility with standard reflow profiles. The PCA8575DK,118 pinout matches other SSOP24 variants of the PCA8575 family, including AD0–AD2 address pins, 16 I/O lines grouped as P00–P07 and P10–P17, and dedicated SCL/SDA/INT/VDD/VSS terminals.

Does the PCA8575DK,118 support 5 V I²C buses?

Yes, the PCA8575DK,118 supports I²C operation with VDD from 2.3 V to 5.5 V and features 5.5 V tolerant I/O pins, including SDA and SCL. This allows direct interfacing with 5 V microcontrollers and legacy systems without level-shifting circuitry. The PCA8575DK,118 maintains Fast-mode I²C compliance (400 kHz) across the full voltage range, with timing parameters validated at both 3.3 V and 5 V operation per the official NXP datasheet Rev. 02.

How does the interrupt (INT) pin behave on the PCA8575DK,118?

The PCA8575DK,118 features an active LOW open-drain INT pin that asserts whenever any rising or falling edge occurs on any of its 16 I/O pins. It deasserts only after the corresponding port data is read (byte-wise clearing) or written. Unlike the PCF8575, the PCA8575DK,118 clears interrupts per port byte: reading P0n clears P00–P07 interrupts, and reading P1n clears P10–P17 interrupts. This enables precise, low-latency event handling without unnecessary bus traffic. The PCA8575DK,118 INT pin requires an external pull-up resistor to VDD.

Can the PCA8575DK,118 directly drive LEDs?

Yes, the PCA8575DK,118 can directly drive standard LEDs with up to 25 mA sink current per I/O pin and a total package sink capability of 400 mA. Its quasi-bidirectional architecture eliminates the need for external current-limiting transistors when used in common-anode LED configurations. Each pin defaults to HIGH at power-up, enabling safe LED off-state initialization. For higher-current loads, two or more pins within the same octal (e.g., P00 + P01) can be paralleled to sink up to 50 mA or 200 mA respectively, as specified in the PCA8575DK,118 datasheet section 10.2.

What are the power-on reset characteristics of the PCA8575DK,118?

The PCA8575DK,118 incorporates an internal Power-On Reset (POR) circuit that holds the device in reset until VDD reaches VPOR (1.8–2.0 V). Upon release, all 16 I/O pins initialize as HIGH-impedance inputs with weak internal pull-ups, ensuring a known safe state before firmware configures direction or logic levels. The POR threshold is independent of temperature and supply ramp rate, and the PCA8575DK,118 requires VDD to drop below 0.2 V to trigger a subsequent reset. This behavior is guaranteed across the full −40 °C to +85 °C operating range.