PCA9555APW,118

I/o Expanders Overview

The PCA9555APW,118 is a low-voltage 16-bit General Purpose Input/Output (GPIO) expander designed for I2C-bus and SMBus applications. It provides 16 bidirectional I/O pins within a TSSOP24 package. The device operates with a supply voltage range of 1.65 V to 5.5 V and supports Fast-mode I2C communication up to 400 kHz. It features an open-drain active LOW interrupt output, Schmitt-trigger inputs, and internal weak pull-up resistors on all I/O pins. The component includes configuration, input, output, and polarity inversion registers, along with an internal power-on reset mechanism.

I/o Expanders Feature Summary

• Provides 16-bit GPIO expansion via I2C/SMBus interface
• Features open-drain interrupt output for state change notification
• Includes internal weak pull-up resistors on all I/O pins
• Supports hardware-selectable slave addresses

I/o Expanders Applications

• ACPI power switches
• Sensor interfaces
• Push button arrays
• LED driving circuits
• Fan control systems

I/o Expanders Procurement Notes

Verify the specific ordering suffix ',118' against the manufacturer's current documentation to confirm packaging details and compliance status. Ensure that the TSSOP24 package variant matches the required board layout specifications. Cross-reference the part number with official distributor catalogs to validate authenticity and traceability before finalizing procurement orders.

I/o Expanders Selection Notes

Select this component when interfacing with microprocessors requiring additional I/O lines while minimizing interconnections. The wide operating voltage range allows compatibility with modern low-power controllers. Consider the integrated weak pull-ups to reduce external component count. Verify that the 400 kHz bus speed meets system timing requirements.

I/o Expanders Part Context

This device belongs to the PCA9555A family, which serves as a pin-to-pin replacement for the standard PCA9555 and PCF8575 devices. It enhances previous generations by offering lower standby current consumption, higher drive capability, and 5 V tolerant I/Os. The architecture maintains register compatibility while introducing improved noise immunity through Schmitt-trigger actions.

I/o Expanders Replacement Considerations

The PCA9555APW is a direct pin-to-pin replacement for the PCA9555 and PCF8575. However, software modifications are required due to enhanced features such as different default states and additional registers. Verify that the host controller firmware can accommodate these architectural differences during migration.