NXP Semiconductors PCA9554TS,112

Overview

The PCA9554TS,112 from NXP Semiconductors is an 8-bit I²C-bus/SMBus GPIO expander in SSOP20 package, providing configurable input/output pins with active-low open-drain interrupt output, 5 V I/O tolerance, and 400 kHz clock support. It operates from 2.3 V to 5.5 V, features polarity inversion and individual I/O configuration, and is used for ACPI power switches, LED control, sensor interfacing, and push-button monitoring in embedded systems.

For engineers reviewing the PCA9554TS,112 datasheet, PCA9554TS,112 pinout, PCA9554TS,112 application, or PCA9554TS,112 equivalent, this page delivers verified register-level functionality, interrupt timing behavior, I/O drive capability under defined VDD conditions, SSOP20 mechanical dimensions, and direct alternatives with documented address and register compatibility differences.

Technical Context

The PCA9554TS,112 implements a synchronous I²C slave interface with four internal registers-Input Port (read-only), Output Port (read/write), Polarity Inversion (read/write), and Configuration (read/write)-all accessible via command-byte addressing without auto-increment. Its interrupt logic activates on input state change when the corresponding I/O is configured as input, and deactivates upon Input Port register read or state reversion.

Power-on reset initializes all I/Os as high-impedance inputs with weak pull-ups, sets Configuration register bits to '1', Output Port to '1', and Polarity Inversion to '0'. The device supports hardware address selection via A0–A2 pins, yielding a fixed base address of 0x20 (PCA9554) or 0x38 (PCA9554A); PCA9554TS,112 corresponds to the PCA9554 variant.

Key Specifications

Pinout & Package

PCA9554TS,112 uses the SSOP20 package (SOT266-1): plastic shrink small outline, 20 leads, 4.4 mm body width, 0.65 mm lead pitch. Pin 1 is marked by index area; exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9554DB,112, PCA9554TS,112 provides two additional usable I/O pins and matches SSOP20 routing density; compared with PCA9554ATS,112, it occupies the lower I²C address range (0x20–0x27), enabling simpler address allocation in systems with fewer expanders.

Availability

PCA9554TS,112 is available at Aetrix Electronics and suitable for industrial control panels, smart HVAC sensor hubs, ACPI power management subsystems, and LED status array drivers requiring stable component supply across extended temperature ranges (−40 °C to +85 °C).

Supply support for PCA9554TS,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 company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCA9554 product line delivers scalable, I²C-compatible GPIO expansion targeting resource-constrained embedded systems where pin count, power efficiency, and interoperability with SMBus infrastructure are critical design constraints.

FAQ

What is the I²C slave address range supported by the PCA9554TS,112?

The PCA9554TS,112 implements the PCA9554 variant with a base 7-bit I²C address of 0x20. Pins A0, A1, and A2 allow selection of one of eight addresses: 0x20 through 0x27. This is distinct from the PCA9554A variant (e.g., PCA9554ATS,112), which uses base address 0x38. The PCA9554TS,112 does not support dynamic address programming - only hardware pin strapping.

Does the PCA9554TS,112 require external pull-up resistors on SDA and SCL lines?

Yes, the PCA9554TS,112 requires external pull-up resistors on both SDA and SCL lines, as it implements open-drain I²C interface logic. Typical values range from 2.2 kΩ to 10 kΩ depending on bus capacitance and speed (100 kHz vs. 400 kHz). The PCA9554TS,112 itself does not integrate internal pull-ups on these lines.

How does the interrupt (INT) pin of the PCA9554TS,112 behave during I/O reconfiguration?

The INT pin of the PCA9554TS,112 may assert falsely if an I/O pin is reconfigured from output to input while its external voltage level differs from the stored value in the Input Port register. This occurs because the interrupt logic compares external pin state against the Input Port register contents. To avoid spurious interrupts, ensure the pin's external state matches the Input Port register before changing its direction in the Configuration register. The PCA9554TS,112 does not suppress this condition in hardware.

Can the PCA9554TS,112 drive LEDs directly, and what are the current limits per I/O pin?

Yes, the PCA9554TS,112 can drive LEDs directly in sink configuration (common-anode). Each I/O pin supports up to 24 mA sink current at VDD = 4.5 V and VOL = 0.5 V, with absolute maximum rating of 50 mA per pin. However, total device output current must not exceed 85 mA, and total I/O current must be externally limited to 100 mA. The PCA9554TS,112 includes no internal current regulation - external series resistors are required for LED current limiting.

Is the PCA9554TS,112 compatible with SMBus 2.0 specifications?

Yes, the PCA9554TS,112 complies with SMBus 2.0 timing and electrical specifications, including timeout behavior, clock stretching support, and voltage thresholds (VIH ≥ 0.7×VDD, VIL ≤ 0.3×VDD). Its 400 kHz maximum clock frequency, noise-filtered SCL/SDA inputs, and interrupt signaling align with SMBus host-controller interaction models. The PCA9554TS,112 is explicitly qualified for SMBus applications per NXP documentation.