NXP Semiconductors PCA9538D,112

Overview

The PCA9538D,112 from NXP Semiconductors is an 8-bit I²C-bus/SMBus GPIO expander with interrupt and active-low reset, housed in a 16-pin SOIC package (SOT162-1). It provides configurable input/output pins, polarity inversion, and low-power operation across 2.3 V to 5.5 V supply, supporting industrial control panels, sensor hubs, and LED driver interfaces.

For engineers reviewing the PCA9538D,112 datasheet, PCA9538D,112 pinout, PCA9538D,112 application, or PCA9538D,112 equivalent, this device delivers verified I²C address flexibility (up to 4 devices), 400 kHz bus support, 5 V-tolerant I/Os, sub-1 µA standby current, and deterministic reset/interrupt timing - critical for embedded systems requiring reliable peripheral expansion without MCU pin exhaustion.

Technical Context

The PCA9538D,112 implements a register-mapped I²C slave interface with four dedicated 8-bit registers: Configuration (I/O direction), Input Port (read-only state), Output Port (writeable output latch), and Polarity Inversion (input logic inversion). All registers are accessible via standard I²C write/read transactions using command bytes 0–3.

Its interrupt output (INT) is open-drain and asserts when any input pin state differs from its corresponding Input Port register value; deassertion occurs on Input Port register read or state reversion. The active-low RESET pin triggers full register initialization identical to power-on reset, independent of VDD cycling.

Key Specifications

Pinout & Package

PCA9538D,112 uses the SO16 plastic small outline package (SOT162-1), 16-lead, body width 7.5 mm, with gull-wing leads and standard JEDEC MS-013 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9538D,112, PCA9554D,112 trades lower system-level power for added internal pull-ups, while TCA6408ADGGR extends voltage and speed range at the cost of register-level compatibility - making PCA9538D,112 optimal for cost-sensitive, 2.3–5.5 V industrial designs prioritizing minimal standby current and polarity flexibility.

Availability

PCA9538D,112 is available at Aetrix Electronics and suitable for industrial control panels, smart sensor hubs, LED driver interfaces, and ACPI power management systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PCA9538D,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 leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with over 50 years of analog and mixed-signal design heritage.

The PCA9538D,112 belongs to NXP's I²C-bus I/O expander product line, engineered specifically for low-power, interrupt-driven peripheral expansion in resource-constrained embedded systems where pin count and power efficiency are critical.

FAQ

What is the maximum I²C clock frequency supported by the PCA9538D,112?

The PCA9538D,112 supports I²C-bus operation up to 400 kHz, complying with Fast-mode I²C specifications. This allows high-speed register access for time-sensitive applications such as real-time sensor polling or rapid LED state updates without bus contention. The device maintains timing integrity across its full 2.3 V to 5.5 V supply range, and PCA9538D,112 datasheet Table 12 confirms tLOW and tHIGH minima of 1.3 µs and 0.6 µs respectively at 400 kHz.

Does the PCA9538D,112 include internal pull-up resistors on its I/O pins?

No, the PCA9538D,112 does not include internal pull-up resistors - this distinguishes it from the PCA9554 series and directly reduces standby current when I/Os are held LOW. External pull-ups must be added where required (e.g., for open-drain outputs or floating inputs), and PCA9538D,112's 5 V-tolerant I/Os allow use of 5 V pull-ups even when VDD = 3.3 V, preserving signal integrity without level shifters.

How does the interrupt output (INT) of the PCA9538D,112 behave during I/O configuration changes?

The PCA9538D,112 INT pin may assert a false interrupt if an I/O pin is reconfigured from output to input while its physical state differs from the stored Input Port register value. This occurs because the Input Port register reflects prior logic levels, not instantaneous pin states. To avoid spurious interrupts, read the Input Port register immediately after changing configuration, or ensure pin states match expected values before switching direction - a behavior explicitly documented in PCA9538D,112 Section 6.5.

What is the operating temperature range for the PCA9538D,112?

The PCA9538D,112 is rated for operation from −40 °C to +85 °C ambient temperature, matching the specification for all non-AEC-Q100 variants in the PCA9538 family. This range is validated per JEDEC JESD22 standards and supports deployment in industrial enclosures, factory automation equipment, and commercial-grade computing platforms. The PCA9538D,112 datasheet Table 2 and Section 8 confirm Tamb = −40 °C to +85 °C for SO16-packaged units.

Can the PCA9538D,112 be used with a 1.8 V microcontroller I²C interface?

No, the PCA9538D,112 requires a minimum VDD of 2.3 V and specifies VIH ≥ 0.7 × VDD for SCL/SDA inputs - meaning at VDD = 2.3 V, VIH min is 1.61 V, which may not reliably recognize 1.8 V logic HIGH from a 1.8 V MCU. For true 1.8 V I²C compatibility, consider alternatives like the TCA6408A (1.65–5.5 V) or level-shifting circuitry. PCA9538D,112 is optimized for 3.3 V and 5 V systems.