1 Features

• Low standby-current consumption of 1 μA max

• I2C to Parallel port expander

• Open-drain active-low interrupt output

• Active-low reset input

• 5-V Tolerant I/O ports

• Compatible with most microcontrollers

• 400-kHz Fast I2C Bus

• Polarity inversion register

• Address by two hardware address pins for use of

up to four devices

• Latched outputs with high-current drive capability

for directly driving LEDs

• Latch-up performance exceeds 100 mA Per

JESD 78, class II

• ESD protection exceeds JESD 22

– 2000-V Human-body model (A114-A)

– 1000-V Charged-device model (C101)

2 Description

This 16-bit I/O expander for the two-line bidirectional

bus (I2C) is designed for 2.3-V to 5.5-V VCC operation.

It provides general-purpose remote I/O expansion for

most microcontroller families via the I2C interface

[serial clock (SCL), serial data (SDA)].

The PCA9539 consists of two 8-bit Configuration

(input or output selection), Input Port, Output Port,

and Polarity Inversion (active-high or active-low

operation) registers. At power-on, the I/Os are

configured as inputs. The system master 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 or output

register. The polarity of the Input Port register can

be inverted with the Polarity Inversion register. All

registers can be read by the system master.