NXP PCA9555 16-bit I²C-Bus and SMBus I/O Expander

The PCA9555 from NXP Semiconductors is a robust 16-bit I²C-bus and SMBus I/O expander designed to provide general-purpose remote I/O expansion for most microcontroller families via the two-line bidirectional bus (I²C). The device's versatility makes it an ideal solution for applications where additional I/Os are needed, including sensors, power switches, LEDs, push buttons, and any other I/Os where the microcontroller has been left with limited I/Os.

This I/O expander provides an efficient way to save microcontroller I/Os by addressing the need for more I/Os or freeing up those resources for other tasks. The PCA9555 consists of two 8-bit Configuration, Input, Output, and Polarity Inversion registers. Each 8-bit port can be independently configured as an input or output, allowing for a flexible and adaptable I/O interface environment.

Key features of the PCA9555 include:

• Operating power supply voltage range of 2.3 V to 5.5 V
• 400 kHz I²C-bus interface (fast-mode)
• Low standby current consumption
• 16 I/O pins which default to 16 inputs at power-up
• Interrupt output which can be configured to reflect any changes in input
• Active LOW reset input
• Compatible with most microcontrollers
• No glitch on power-up
• Internal power-on reset
• Noise filter on SDA/SCL inputs
• ESD protection exceeds 2000 V HBM per JESD22-A114, and 1000 V CDM per JESD22-C101
• Latch-up testing is done to JESDEC Standard JESD78 which exceeds 100 mA
• Packaged in 24-pin SO, TSSOP, HVQFN

The PCA9555 is available in several packages, including DIP, SO, and TSSOP, making it suitable for a wide range of applications. The device also features an interrupt output for input change notification, which can be helpful in optimizing system power consumption by eliminating the need for the microcontroller to poll the input status.

Whether you're designing industrial control systems, servers, or any other system requiring additional I/Os, the PCA9555 is a reliable and cost-effective solution that simplifies design and enhances functionality.