NXP Semiconductors PCA8574ATS,112

Overview

PCA8574ATS,112 from NXP Semiconductors is an 8-bit quasi-bidirectional I/O expander for I²C-bus (Fast-mode, 400 kHz), operating from 2.3 V to 5.5 V with 5.5 V-tolerant I/Os, featuring active-low open-drain interrupt output (INT), eight hardware-addressable slave addresses via A0–A2, and 25 mA per-pin sink capability for direct LED drive in SSOP20 package.

For engineers reviewing the PCA8574ATS,112 datasheet, PCA8574ATS,112 pinout, PCA8574ATS,112 application, or PCA8574ATS,112 equivalent, this device serves as a remote parallel port extension for microcontroller GPIO expansion in space-constrained industrial and mobile systems requiring low standby current (4.5 µA typical) and interrupt-driven input monitoring without polling.

Technical Context

The PCA8574ATS,112 implements a single-register quasi-bidirectional I/O architecture: each of P0–P7 functions as input or output without direction register, defaulting to HIGH inputs at power-on via 100 µA internal pull-up. Input state changes trigger the INT pin, which resets on read/write acknowledgment or return to original state.

It uses Fast-mode I²C (400 kHz) with fixed 7-bit slave address 0x70–0x77 (PCA8574A variant), supports up to 128 total I/Os when combined with seven other PCA8574/74A devices on one bus, and features Power-On Reset (POR) that initializes all ports as inputs with weak pull-up - no external reset required.

Key Specifications

Pinout & Package

PCA8574ATS,112 is housed in SSOP20 (plastic shrink small outline package, 20 leads, 4.4 mm body width), pin-compatible with other PCA8574A variants in SSOP20 footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C-based remote I/O expansion applications.

Compared with PCA8574TS,112 and PCA9674APW,118, the PCA8574ATS,112 delivers proven industrial reliability in SSOP20 with optimized interrupt latency and ultra-low standby current, making it ideal for cost-sensitive, space-constrained legacy and mid-volume applications where address flexibility and pin compatibility are prioritized over next-gen speed or density.

Availability

PCA8574ATS,112 is available at Aetrix Electronics and suitable for industrial control panels, medical equipment interfaces, and LED signage requiring stable component supply, long-term lifecycle support, and consistent SSOP20 packaging.

Supply support for PCA8574ATS,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 peripherals and embedded interface ICs.

The PCA8574ATS,112 belongs to NXP's remote I/O expander product line, designed specifically to extend microcontroller GPIO count over I²C with minimal firmware overhead, low power, and interrupt-driven event handling for resource-constrained embedded systems.

FAQ

What is the I²C slave address range for PCA8574ATS,112?

The PCA8574ATS,112 is the PCA8574A variant and uses a fixed 7-bit slave address range of 0x70 to 0x77 (hex), determined by the logic states of address pins A2–A0. This differs from the PCA8574 (0x40–0x47) and allows up to eight PCA8574ATS,112 devices to coexist on the same I²C bus without address collision.

Can PCA8574ATS,112 drive LEDs directly without external components?

Yes, the PCA8574ATS,112 supports direct LED drive: each of its eight I/O pins provides 25 mA sink current at 4.5 V, sufficient for standard indicator LEDs. A current-limiting resistor is still required per LED anode (connected to VDD), but no external transistor or driver IC is needed - simplifying BOM and layout.

How does the interrupt (INT) pin of PCA8574ATS,112 operate?

The INT pin on PCA8574ATS,112 is an active-low open-drain output that asserts LOW whenever any input state (P0–P7) differs from its corresponding register value. It de-asserts (goes HIGH) upon reading the input register or writing to the port - enabling efficient event-driven polling instead of continuous I²C reads.

What is the power-on behavior of PCA8574ATS,112 I/O pins?

At power-on, PCA8574ATS,112 performs an internal Power-On Reset (POR) that configures all eight I/O pins (P0–P7) as HIGH inputs with a 100 µA internal pull-up to VDD. This eliminates the need for external pull-up resistors on inputs and ensures predictable startup state before firmware initialization.

Is PCA8574ATS,112 pin-compatible with other PCA8574A packages?

Yes - PCA8574ATS,112 in SSOP20 shares identical pin functions and numbering with PCA8574APW (TSSOP16) and PCA8574AD (SO16), though physical pin spacing and count differ. The SSOP20 variant has four additional n.c. pins (3, 8, 13, 18) and relocated address/I/O assignments versus SO16/TSSOP16, so PCB layout is not interchangeable.