NXP Semiconductors PCA9539PW,118

Overview

PCA9539PW,118 from NXP Semiconductors is a 24-pin TSSOP I²C/SMBus 16-bit GPIO expander with active-low interrupt and hardware reset, operating from 2.3 V to 5.5 V, supporting up to 400 kHz clock rate, and featuring 5 V tolerant I/Os for mixed-voltage system interfacing in industrial control panels.

For engineers reviewing the PCA9539PW,118 datasheet, PCA9539PW,118 pinout, PCA9539PW,118 application, or PCA9539PW,118 equivalent, this page delivers verified register-level I/O configuration, interrupt behavior, reset semantics (full register + state machine reset), package-specific thermal pad requirements, and direct alternative comparisons for embedded I/O expansion design-in.

Technical Context

The PCA9539PW,118 implements two independent 8-bit I/O ports (Port 0 and Port 1), each with dedicated configuration, input, output, and polarity inversion registers - enabling per-pin direction control and active-HIGH/LOW input inversion without external logic. Its interrupt output is open-drain and asserts when any configured input pin state differs from its corresponding input port register value.

Unlike the PCA9539R variant, the PCA9539PW,118 uses the RESET pin to fully reset both the I²C-bus state machine and all internal registers (configuration, output, polarity) to power-on defaults; the pin requires an external pull-up to VDD and must be held LOW for ≥t_w(rst) to trigger. It lacks internal I/O pull-up resistors, reducing standby current when outputs drive LOW.

Key Specifications

Pinout & Package

TSSOP24 package (SOT355-1), 4.4 mm body width, 24-lead thin shrink small outline; exposed pad not present - no thermal pad soldering required.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar GPIO expander applications.

Compared with PCA9555PW,118, PCA9539PW,118 reduces standby current by eliminating internal pull-ups; compared with PCA9539RPW,118, it provides full functional reset - making it optimal for applications requiring guaranteed deterministic I/O initialization after fault recovery.

Availability

PCA9539PW,118 is available at Aetrix Electronics and suitable for industrial control panels, smart sensor hubs, ACPI power management subsystems, and keypad/status indicator modules requiring stable component supply across extended temperature ranges (−40 °C to +85 °C).

Supply support for PCA9539PW,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, with deep expertise in I²C ecosystem components and embedded interface IP.

The PCA9539 product line delivers low-power, interrupt-capable GPIO expansion for resource-constrained microcontrollers - designed specifically for industrial automation, building control, and embedded systems needing reliable, scalable I/O without sacrificing bus efficiency.

FAQ

What is the function of the RESET pin on the PCA9539PW,118?

The RESET pin on the PCA9539PW,118 is an active-low input that synchronously resets the entire device: all internal registers (configuration, output, polarity, input) and the I²C-bus state machine return to their power-on default values. This full reset ensures deterministic I/O initialization and is distinct from the PCA9539R variant, which retains register contents. The PCA9539PW,118 requires an external pull-up to VDD and must be held LOW for ≥t_w(rst) to activate.

Does the PCA9539PW,118 support 5 V logic levels on its I/O pins?

Yes, the PCA9539PW,118 features 5 V tolerant I/Os - meaning all 16 GPIO pins (IO0_0 through IO1_7) can safely accept input voltages up to 5.5 V regardless of the VDD supply voltage (2.3 V–5.5 V). This allows direct interfacing with 5 V peripherals such as switches, LEDs, or sensors in mixed-voltage systems without external level shifters.

How does the interrupt output (INT) behave on the PCA9539PW,118?

The INT pin on the PCA9539PW,118 is an active-low open-drain output that asserts when any I/O pin configured as an input changes state relative to its corresponding bit in the input port register. The interrupt clears automatically upon reading the relevant input port register (Port 0 or Port 1), and cannot be triggered by output-configured pins. It requires an external pull-up resistor to function correctly.

What I²C address options are available for the PCA9539PW,118?

The PCA9539PW,118 uses a fixed 7-bit base address of 11101xx, where the two LSBs (xx) are set by hardware pins A0 and A1. With A0 and A1 tied HIGH/LOW, four unique addresses are possible: 0x74, 0x75, 0x76, or 0x77. This allows up to four PCA9539PW,118 devices to share the same I²C bus without address conflict.

Is the PCA9539PW,118 pin-compatible with other members of the PCA9539 family?

Yes, the PCA9539PW,118 is pin-compatible with all TSSOP24 variants in the PCA9539 family, including PCA9539PW/Q900 (AEC-Q100 qualified) and PCA9539RPW,118. All share identical pin numbering, electrical characteristics, and register mapping - differing only in RESET functionality (full vs. partial reset) and qualification grade. No PCB layout changes are needed when substituting within the TSSOP24 footprint.