PCA9554ARGTR

I/o Expanders Overview

The PCA9554ARGTR is an 8-bit I/O expander for the two-line bidirectional I2C bus, designed for 2.3-V to 5.5-V VCC operation. It provides general-purpose remote I/O expansion via the I2C interface and consists of one 8-bit Configuration register, Input Port register, Output Port register, and Polarity Inversion register. The device features an open-drain active-low interrupt output that activates when any input state differs from its corresponding Input Port register state. Three hardware address pins (A0, A1, A2) allow up to eight devices to share the same I2C/SMBus. The outputs have high-current drive capability for directly driving LEDs, with a maximum sink current of 25 mA per pin and a total port limit of 200 mA.

I/o Expanders Feature Summary

• Open-drain active-low interrupt output signals system master on input state changes
• Three hardware address pins enable up to eight devices on a single I2C/SMBus
• Internal power-on reset initializes registers and I2C/SMBus state machine
• Push-pull design structure for P-port inputs/outputs

I/o Expanders Applications

• Remote I/O expansion for microcontroller families
• Direct LED driving applications
• ACPI power switch interfaces
• Sensor and button interfacing

I/o Expanders Procurement Notes

Verify the ordering suffix 'RTR' corresponds to the RGT package type as specified in the datasheet's Device Information table. Confirm the specific revision level required for your application, noting potential errata regarding interrupt handling during ACK/NACK pulses. Ensure compatibility with existing software drivers due to differences from legacy PCF8574 series devices.

I/o Expanders Selection Notes

Select this component when 8-bit I/O expansion is required with interrupt capabilities. It is suitable for systems operating between 2.3 V and 5.5 V. Consider the RGT package size if space constraints are critical. Verify that the I2C bus speed requirements do not exceed 400 kHz. Check if the fixed I2C address of the PCA9554A variant fits within your available bus addresses alongside other PCA9554 devices.

I/o Expanders Part Context

The PCA9554A is part of Texas Instruments' I/O expander family, offering enhanced features over the PCF8574 series such as higher drive capability and configurable polarity. It shares pinout compatibility but requires software adjustments. The PCA9554 and PCA9554A differ only in their fixed I2C addresses, allowing up to 16 devices on the same bus when mixed.

I/o Expanders Replacement Considerations

PCF8574A: Pin-compatible but lacks configuration registers and interrupt functionality; requires significant software changes. PCA9554: Identical functionality except for a different fixed I2C address.