PCA9554ATS,112

I/o Expanders Overview

The PCA9554ATS,112 is an 8-bit I/O expander from the PCA9554 family, designed for I2C-bus and SMBus applications. It provides General Purpose parallel Input/Output expansion in a 20-lead SSOP package (SOT266-1). The device operates within a supply voltage range of 2.3 V to 5.5 V and supports clock frequencies up to 400 kHz. It features an active LOW open-drain interrupt output, polarity inversion registers, and hardware-selectable addresses via A0, A1, and A2 pins. The component includes noise filters on SCL/SDA inputs and internal power-on reset functionality.

I/o Expanders Feature Summary

• Provides 8 bits of GPIO expansion with individual input/output configuration capabilities
• Features an active LOW open-drain interrupt output triggered by input state changes
• Includes a polarity inversion register to modify read data logic levels
• Supports multiple devices on the same bus through three hardware address pins

I/o Expanders Applications

• ACPI power switches
• Sensor interface expansion
• Push button matrix scanning
• LED driver control
• Fan speed monitoring

I/o Expanders Procurement Notes

Verify the specific ordering suffix against current NXP documentation to confirm package type and marking details. Confirm that the SSOP20 variant matches the required footprint dimensions. Check for any end-of-life notices or obsolescence warnings associated with this specific part number before finalizing procurement plans.

I/o Expanders Selection Notes

Select this component when an 8-bit I/O expansion solution is required with interrupt capability. Ensure the system design accommodates the 20-lead SSOP package size. Verify that the fixed I2C address of the PCA9554 variant aligns with the available address space on the target bus alongside other devices.

I/o Expanders Part Context

This part belongs to the PCA9554 series of CMOS I/O expanders developed to enhance previous generations with higher drive capability and lower supply current. It serves as a direct pin-to-pin compatible alternative to the PCF8574 series, though software modifications are necessary due to architectural differences such as the inclusion of configuration and polarity inversion registers.

I/o Expanders Replacement Considerations

The PCA9554ATS is functionally identical to the PCA9554TS regarding electrical performance but differs in its fixed I2C slave address. When replacing existing units, ensure the new address does not conflict with other devices on the bus.