PCA9537

4-bit I2C-bus and SMBus low power I/O port with interrupt and

reset

Rev. 7 — 8 September 2021

Product data sheet

COMPANY PUBLIC

1 General description

The PCA9537 is a 10-pin CMOS device that provides 4 bits of General Purpose parallel

Input/Output (GPIO) expansion with interrupt and reset for I2C-bus/SMBus applications.

It was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders.

I/O expanders provide a simple solution when additional I/O is needed for ACPI power

switches, sensors, push-buttons, LEDs, fans, etc.

The PCA9537 consists of a 4-bit Configuration register (input or output selection), 4-bit

Input Port register, 4-bit Output Port register and a 4-bit Polarity Inversion register (active

HIGH or active LOW operation). The system controller can enable the I/Os as either

inputs or outputs by writing to the I/O configuration bits. The data for each input or output

is kept in the corresponding Input Port or Output Port register. The polarity of the Input

Port register can be inverted with the Polarity Inversion register. All registers can be read

by the system controller.

The PCA9537 open-drain interrupt output (INT) is activated when any input state differs

from its corresponding Input Port register state and is used to indicate to the system

controller that an input state has changed. The power-on reset sets the registers to their

default values and initializes the device state machine. The RESET pin causes the same

reset/initialization to occur without de-powering the device.

The I2C-bus address is fixed and allows only one device on the same I2C-bus/SMBus.

2 Features and benefits

• 4-bit I2C-bus GPIO with interrupt and reset

• Operating power supply voltage range of 2.3 V to 5.5 V

• 5 V tolerant I/Os

• Polarity Inversion register

• Active LOW interrupt output

• Active LOW reset input

• Low standby current

• Noise filter on SCL/SDA inputs

• No glitch on power-up

• Internal power-on reset

• 4 I/O pins that default to 4 inputs

• 0 Hz to 400 kHz clock frequency

• ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per JESD22-A115

and 1000 V CDM per JESD22-C101

• Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA

• Offered in TSSOP10 package