CAT9554AYGI-T2

Overview

The CAT9554AYI-GT2 is an 8-bit I/O expander designed for I2C and SMBus applications, manufactured by onsemi. It operates within a supply voltage range of 2.3 V to 5.5 V and supports clock frequencies up to 400 kHz. The device features push-pull outputs with drive currents of 10 mA (sink) and 24 mA (source). It includes an interrupt output capability and a Power-On Reset (POR) function. The component is housed in a 16-TSSOP package with a width of 4.40 mm and functions reliably across a temperature range of -40°C to +85°C.

Feature Summary

• Provides 8-bit general-purpose parallel input/output expansion via I2C/SMBus interface
• Includes open-drain interrupt output to notify the host of input state changes
• Features hardware address pins allowing multiple devices on the same bus
• Integrates Power-On Reset logic to initialize registers upon power-up

Applications

• ACPI power switch implementations requiring additional GPIO control
• Sensor interface modules needing expanded input capabilities
• Button matrix scanning systems for user input detection
• LED driver arrays controlled via serial communication protocols

Procurement Notes

Verify the exact suffix configuration against current datasheets, as manufacturing updates may affect package or electrical specifications. Confirm RoHS compliance status through official documentation. Check for product discontinuance notifications from onsemi, as this series has faced end-of-life announcements. Ensure the supplier provides valid traceability for the specific lot code required for your assembly process.

Selection Notes

Select this component when an 8-bit I/O expansion solution is required with moderate drive strength. Compare against the PCA9554 for pin compatibility, noting that software adjustments may be necessary due to enhanced features. Consider the CAT9555 if 16-bit expansion is needed instead. Verify that the 400 kHz SMBus speed meets system timing requirements and that the TSSOP package fits the PCB footprint constraints.

Part Context

This part belongs to the CAT9554A family of I/O expanders, originally developed by Catalyst Semiconductor before its acquisition by onsemi. The family shares architectural similarities with NXP's PCA9554 series but offers improved drive capabilities and lower power consumption. The 'YI' suffix typically denotes the TSSOP-16 package variant, while 'GT2' indicates tape and reel packaging for surface-mount assembly.

Replacement Considerations

The NXP PCA9554 is a pin-compatible alternative, though software modifications are required due to functional differences. The CAT9555WI offers 16-bit expansion in a similar form factor. Verify that any substitute maintains the 2.3V to 5.5V operating range and interrupt functionality to ensure system compatibility without hardware redesign.