NXP Semiconductors PCA9554DB,112

Overview

PCA9554DB,112 from NXP Semiconductors is an 8-bit I²C-bus/SMBus GPIO expander in SSOP16 package, supporting 2.3 V to 5.5 V supply, 5 V-tolerant I/Os, and 400 kHz clock frequency. It provides configurable input/output pins, polarity inversion, and active-low open-drain interrupt output for ACPI power switches, LED control, sensor interfacing, and push-button monitoring.

For engineers reviewing the PCA9554DB,112 datasheet, PCA9554DB,112 pinout, PCA9554DB,112 application, or PCA9554DB,112 equivalent, key selection criteria include I²C address configuration via A0–A2 pins, register-level I/O direction control, interrupt-driven state change detection, low standby current (≤700 µA), and compatibility with industrial temperature range (−40 °C to +85 °C).

Technical Context

The PCA9554DB,112 implements a register-mapped I²C slave interface with four dedicated 8-bit registers: Configuration (input/output direction), Input Port (read-only pin state), Output Port (writeable output latch), and Polarity Inversion (bitwise read inversion). All registers are accessible via standard I²C write/read transactions using command-byte addressing without auto-increment.

Its interrupt logic activates on any input-state mismatch against the Input Port register value, requiring explicit read of that register to clear. Power-on reset initializes all I/Os as high-impedance inputs with internal 100 kΩ pull-ups, and noise filtering on SCL/SDA ensures robust bus operation in electrically noisy environments.

Key Specifications

Pinout & Package

PCA9554DB,112 is housed in a plastic shrink small outline package (SSOP16) with 16 leads and 5.3 mm body width (SOT338-1). Pin 1 is marked by index area; device orientation follows JEDEC MO-150 standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9554D,112, PCA9554DB,112 saves 30% board area with its narrower SSOP16 package while maintaining full register and timing compatibility; compared with PCA9554ADB,112, it shares identical physical design but offers distinct I²C addressing for bus segmentation without hardware modification.

Availability

PCA9554DB,112 is available at Aetrix Electronics and suitable for industrial control panels, embedded sensor hubs, ACPI power management subsystems, and LED status array drivers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for PCA9554DB,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 family was designed specifically to extend I²C-bus GPIO capability in resource-constrained embedded systems, emphasizing low power, industrial temperature operation, and seamless integration with existing SMBus infrastructure.

FAQ

What is the I²C slave address of PCA9554DB,112?

The PCA9554DB,112 uses a fixed 7-bit I²C slave address of 0x20, determined by its PCA9554 (not PCA9554A) variant designation. Address bits A0–A2 allow hardware selection of one of eight possible addresses (0x20–0x27) within this base range. This differs from the PCA9554A series, which starts at 0x38. The PCA9554DB,112's address is confirmed in Figure 9 of the official NXP datasheet Rev. 10.

Does PCA9554DB,112 support hot insertion or live I²C bus connection?

No, PCA9554DB,112 does not support hot insertion. Its power-on reset circuit requires VDD to drop below 0.2 V for at least 5 µs to fully initialize registers, and applying I²C signals before VDD stabilization may cause undefined behavior or bus contention. The PCA9554DB,112 must be powered and stabilized prior to enabling SCL/SDA communication, as specified in Section 6.2 of the datasheet.

Can PCA9554DB,112 drive LEDs directly without external current-limiting resistors?

PCA9554DB,112 can sink up to 10 mA per I/O pin at VOL = 0.5 V (VDD = 3.0 V), but external current-limiting resistors are still required to set precise LED current and protect against overvoltage. The device lacks internal current regulation; resistor selection must ensure total sourced current remains ≤85 mA and individual pin current stays ≤25 mA, per Table 10 and footnote [2] in the PCA9554_9554A datasheet.

How does the interrupt output (INT) behave when multiple input pins change simultaneously on PCA9554DB,112?

When multiple input pins change state, PCA9554DB,112 asserts the open-drain INT line low and holds it until the Input Port register is read - regardless of how many pins changed. The INT signal does not encode which pin(s) triggered it; software must read the Input Port register to determine changed bits, then compare against the previous state. This behavior is defined in Section 6.3 and Figure 14 of the datasheet.

Is PCA9554DB,112 pin-compatible with PCF8574-series I/O expanders?

PCA9554DB,112 is pin-to-pin compatible with PCF8574 devices in the same package variant (e.g., SSOP16), sharing identical pin functions and locations. However, software is not compatible due to differences in register mapping, interrupt implementation, and configuration logic - requiring firmware updates per Application Note AN469. The PCA9554DB,112 retains the same physical layout but extends functionality beyond the PCF8574 baseline.