NXP Semiconductors PCAL9554BBSHP

Overview

PCAL9554BBSHP from NXP Semiconductors is an 8-bit I²C-bus/SMBus GPIO expander with Agile I/O features, interrupt output, and weak pull-up resistors. It operates from 1.65 V to 5.5 V, supports 400 kHz Fast-mode I²C, provides 25 mA sink per I/O, and powers up with all pins configured as inputs - enabling reliable board bring-up in ACPI power switches, LED/fan control, and sensor interfaces.

For engineers reviewing the PCAL9554BBSHP datasheet, PCAL9554BBSHP pinout, PCAL9554BBSHP application, or PCAL9554BBSHP equivalent, this device delivers programmable drive strength, latchable inputs, maskable interrupts, interrupt status reporting, and bank-selectable push-pull/open-drain outputs - critical for deterministic I/O expansion in resource-constrained embedded systems.

Technical Context

The PCAL9554BBSHP implements a dual-register I²C interface with standard PCA9554A-compatible registers (Input/Output/Polarity/Configuration) plus extended Agile I/O registers (drive strength, input latch, pull-up/down enable/selection, interrupt mask/status, output configuration). Its interrupt logic responds to edge transitions on any unmasked input pin and latches state changes until the Input Port register is read.

Hardware address selection via A0–A2 pins enables up to eight devices on one bus; the PCAL9554B variant uses fixed slave address 0x20 (0100xxx), distinct from PCAL9554C's 0x38 (0111xxx). Internal power-on reset ensures glitch-free initialization with all interrupts masked and I/Os set as high-impedance inputs.

Key Specifications

Pinout & Package

HVQFN16 package (3 mm × 3 mm × 0.85 mm body, exposed thermal pad); RoHS-compliant, leadless quad flat no-lead construction with 16 terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C GPIO expander applications.

Compared with PCA9554APW and TCA6408APWR, PCAL9554BBSHP provides superior debuggability via interrupt status reporting, deterministic event capture via input latching, and signal integrity tuning via per-pin drive strength - making it optimal for real-time embedded control where I/O behavior must be precisely managed.

Availability

PCAL9554BBSHP is available at Aetrix Electronics and suitable for ACPI power management, LED/fan control, sensor interface hubs, pushbutton monitoring, and industrial I/O expansion requiring stable component supply across long-life production cycles.

Supply support for PCAL9554BBSHP 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 interface and power management ICs.

The PCAL9554BBSHP belongs to NXP's Agile I/O GPIO expander family, designed specifically to extend microcontroller I/O count while delivering advanced configurability - including interrupt diagnostics, drive optimization, and noise-immune input handling - for demanding embedded control systems.

FAQ

What is the I²C slave address of PCAL9554BBSHP?

The PCAL9554BBSHP uses a fixed 7-bit I²C slave address of 0x20 (0100xxx), where the three least-significant bits are determined by hardware pins A2, A1, and A0. This base address distinguishes it from the PCAL9554C variant (0x38) and allows up to eight PCAL9554BBSHP devices on a single I²C bus without address conflict. The full address byte includes R/W bit (0 for write, 1 for read).

Does PCAL9554BBSHP support 5 V tolerant I/Os?

Yes, PCAL9554BBSHP supports 5 V tolerant I/Os across its full VDD range (1.65 V to 5.5 V). This means all P0–P7 pins can safely interface with 5 V logic signals even when VDD is supplied at 1.8 V or 3.3 V - enabling seamless level translation in mixed-voltage systems without external voltage translators or clamping diodes.

How does the interrupt masking work on PCAL9554BBSHP?

PCAL9554BBSHP uses an 8-bit Interrupt Mask register (address 0x45) where each bit corresponds to one I/O pin. A value of '1' masks that pin's interrupt (no INT assertion on state change); '0' enables it. At power-up, all mask bits default to '1', preventing spurious interrupts during system initialization - a key feature for reliable board bring-up in ACPI and industrial control applications.

Can PCAL9554BBSHP directly drive LEDs?

Yes, PCAL9554BBSHP can directly drive LEDs with up to 25 mA sink current per I/O pin (P0–P7). Its programmable output drive strength allows fine-tuning of rise/fall times, and its open-drain or push-pull output configuration supports both common-anode and common-cathode LED topologies - eliminating the need for external current-limiting transistors in many designs.

What is the purpose of the input latch feature in PCAL9554BBSHP?

The input latch feature in PCAL9554BBSHP ensures that a change in input state is retained in the Input Port register until explicitly read - even if the physical pin returns to its original logic level before the register is accessed. This prevents missed events in interrupt-driven firmware and guarantees deterministic capture of transient switch closures or sensor pulses, especially in low-power polling intervals.