NXP Semiconductors PCA8574TS,118

Overview

PCA8574TS,118 from NXP Semiconductors is an 8-bit quasi-bidirectional I/O expander for I²C-bus (SCL/SDA), operating from 2.3 V to 5.5 V with 400 kHz Fast-mode support. It features eight I/O pins (P0–P7), active-low open-drain interrupt (INT), three hardware address inputs (A0–A2), and latched outputs with 25 mA sink capability per pin-enabling direct LED drive in compact industrial control panels.

For engineers reviewing the PCA8574TS,118 datasheet, PCA8574TS,118 pinout, PCA8574TS,118 application, or PCA8574TS,118 equivalent, this device delivers low-power remote GPIO expansion with interrupt-driven change detection, 200 mA total package sink current, and SSOP20 packaging suitable for space-constrained embedded designs requiring stable I²C peripheral extension.

Technical Context

The PCA8574TS,118 implements a single-register quasi-bidirectional I/O architecture: each port pin functions as input or output without direction register overhead, defaulting to HIGH at power-on via 100 µA internal pull-up. Input state changes trigger the INT pin, eliminating continuous polling.

Its I²C slave address is configurable across eight values using A0–A2 (PCA8574 base address 0x40–0x47), and it supports concurrent operation with up to seven other PCA8574/74A devices on the same bus. The SSOP20 package accommodates all 20 pins-including four n.c. terminals-while maintaining full functional equivalence to SO16/TSSOP16 variants.

Key Specifications

Pinout & Package

PCA8574TS,118 is housed in a plastic shrink small outline package (SSOP20) with 20 leads, 4.4 mm body width, and exposed pad thermal performance optimized for surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C I/O expander applications.

Compared with PCA8574TS,118, PCA8574D,518 offers identical functionality in a larger SO16 package for easier assembly, while PCA9674APW,118 provides faster I²C, more addresses, and noise-immune inputs-making it suitable for next-generation industrial networks where scalability and EMI resilience are critical.

Availability

PCA8574TS,118 is available at Aetrix Electronics and suitable for industrial PLCs, medical front panels, server management cards, and LED signage controllers requiring stable component supply across multi-year production cycles.

Supply support for PCA8574TS,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.

The PCA8574 family was designed to simplify I²C-based GPIO expansion in resource-constrained embedded systems-delivering low-power, interrupt-aware remote I/O with minimal firmware overhead.

FAQ

What is the I²C slave address range for PCA8574TS,118?

The PCA8574TS,118 uses the PCA8574 base address format: 7-bit address 0x40–0x47 (hex), determined by A2/A1/A0 pin states. For example, A2=A1=A0=LOW yields 0x40 (write) / 0x41 (read). This matches PCF8574TS/3 compatibility per NXP ordering documentation.

Does PCA8574TS,118 require external pull-up resistors on SDA and SCL lines?

Yes, PCA8574TS,118 requires external pull-up resistors on both SDA and SCL lines-typically 2.2 kΩ to 4.7 kΩ-to ensure proper I²C bus signaling. The device itself does not integrate internal pull-ups on these lines.

Can PCA8574TS,118 drive LEDs directly without current-limiting resistors?

No-PCA8574TS,118 requires a series current-limiting resistor for each LED. While its 25 mA sink capability supports direct drive, omitting the resistor risks exceeding absolute maximum ratings and damaging the output transistor or LED.

How does the interrupt (INT) pin behave during power-on reset?

At power-on, PCA8574TS,118 initializes all I/Os as inputs with 100 µA pull-up. If any port pin is externally pulled LOW (e.g., grounded button), the INT pin asserts LOW immediately after POR completes-signaling initial state change to the host MCU.

Is PCA8574TS,118 pin-compatible with PCF8574TS/3?

Yes-PCA8574TS,118 is documented as a drop-in replacement for PCF8574TS/3 (per NXP Table 1 footnote [3]), sharing identical SSOP20 pinout, electrical characteristics, and I²C protocol behavior.