NXP Semiconductors PCA9502BS,157

Overview

PCA9502BS,157 from NXP Semiconductors is an 8-bit I/O expander with dual-mode I²C-bus or SPI host interface, operating at 2.5 V or 3.3 V, supporting industrial temperature range (−40 °C to +85 °C), software reset, and 16 hardware-selectable slave addresses - deployed in portable, battery-operated devices requiring compact GPIO expansion.

For engineers reviewing the PCA9502BS,157 datasheet, PCA9502BS,157 pinout, PCA9502BS,157 application, or PCA9502BS,157 equivalent, this page delivers verified interface modes (I²C Fast-mode up to 400 kbit/s or SPI up to 15 Mbit/s), HVQFN24 package mapping, GPIO register control behavior, IRQ interrupt latching logic, and validated alternative parts for embedded I/O extension designs.

Technical Context

The PCA9502BS,157 implements a dual-interface architecture where the I2C/SPI select pin (Pin 4) statically configures operation mode at power-up: HIGH enables I²C-bus slave mode (Fast-mode compliant, noise-filtered SCL/SDA), LOW enables SPI slave mode (Mode 0, 15 Mbit/s max). Both interfaces share identical register map (IODir, IOState, IOIntEna, IOControl) and GPIO[7:0] functionality.

Interrupt generation is edge-triggered on GPIO input state change and controlled via IOIntEna register; IRQ output is open-drain with external pull-up (1 kΩ @ 3.3 V, 1.5 kΩ @ 2.5 V). Software reset is executed by writing '1' to bit 3 (SReset) of IOControl register (0x0E), clearing all configuration registers to default states without affecting hardware reset timing.

Key Specifications

Pinout & Package

HVQFN24 package (SOT616-3) with 24 terminals, 4 mm × 4 mm body, 0.85 mm height, and exposed center thermal pad requiring PCB ground connection.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I/O expander applications.

Compared with PCA9502BS,157, PCA9555D,118 offers double the I/O count but sacrifices SPI compatibility and software reset; MCP23017-E/SP provides 5 V tolerance but mandates layout changes and removes critical runtime reset control - making PCA9502BS,157 optimal for space-constrained, dual-interface, low-power embedded designs.

Availability

PCA9502BS,157 is available at Aetrix Electronics and suitable for factory automation, portable medical devices, and cellular IoT modems requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for PCA9502BS,157 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 mixed-signal ICs.

The PCA9502BS,157 belongs to NXP's I/O expander product line, designed specifically for compact, low-power embedded systems needing flexible host interface options and deterministic interrupt-driven GPIO control.

FAQ

What interface protocols does the PCA9502BS,157 support?

The PCA9502BS,157 supports two mutually exclusive host interfaces selected at power-up: I²C-bus (Fast-mode, up to 400 kbit/s) or SPI (Mode 0, up to 15 Mbit/s). The I2C/SPI pin (Pin 4) determines mode - HIGH for I²C, LOW for SPI. Both interfaces access the same register set (IODir, IOState, IOIntEna, IOControl) and GPIO[7:0] functionality, enabling consistent firmware abstraction across protocols.

How does the software reset function work on the PCA9502BS,157?

Software reset on the PCA9502BS,157 is triggered by writing '1' to bit 3 (SReset) of the IOControl register (address 0x0E). This action clears all configuration registers (IODir, IOIntEna, IOControl) to their power-on defaults and forces GPIO pins into high-impedance input mode. The SReset bit auto-clears to '0' after execution, and no external RESET pin assertion is required - enabling full device recovery from firmware without hardware intervention.

What are the GPIO interrupt capabilities of the PCA9502BS,157?

The PCA9502BS,157 generates interrupts on GPIO input state changes via the open-drain IRQ pin (Pin 12). Interrupt sources are individually enabled per GPIO using the IOIntEna register (0x0C). Latching behavior is controlled by the IOLatch bit (IOControl[0]): when set, input state changes are captured in IOState register and persist until read; when cleared, interrupts are edge-triggered and cleared on IOState read. External pull-up (1 kΩ @ 3.3 V) is mandatory for IRQ operation.

Can the PCA9502BS,157 operate at both 2.5 V and 3.3 V supply voltages?

Yes, the PCA9502BS,157 is fully specified for operation at either 2.5 V ±0.2 V or 3.3 V ±0.3 V, with corresponding static supply current of ≤600 µA (both conditions). Input thresholds scale accordingly: VIH is ≥1.6 V (2.5 V supply) or ≥2.0 V (3.3 V supply); IRQ pull-up resistors must match supply voltage (1.5 kΩ for 2.5 V, 1 kΩ for 3.3 V) to ensure valid logic levels and drive strength.

What package type and thermal requirements apply to the PCA9502BS,157?

The PCA9502BS,157 uses the HVQFN24 package (SOT616-3), measuring 4 mm × 4 mm × 0.85 mm with an exposed center thermal pad. This pad must be soldered to a PCB ground plane to meet thermal and electrical specifications - failure to connect it degrades thermal performance and may cause reliability issues. Pin pitch is 0.5 mm, requiring standard fine-pitch reflow processes compatible with automated assembly.