PCA9554ADB

I/o Expanders Overview

The PCA9554ADB 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 features a 400-kHz Fast I2C Bus. The device includes three hardware address pins (A0, A1, A2) allowing up to eight devices on the same bus. It consists of Configuration, Input, Output, and Polarity Inversion registers. At power-on, I/Os are configured as inputs with a weak pullup to VCC. The open-drain active-low interrupt output indicates input state changes. It operates within a temperature range of -40°C to +85°C.

I/o Expanders Feature Summary

• Open-Drain Active-Low Interrupt Output
• 5-V Tolerant I/Os
• Input/Output Configuration Register
• Polarity Inversion Register

I/o Expanders Applications

• ACPI power switches
• Sensors
• Push buttons
• LEDs
• Fans

I/o Expanders Procurement Notes

Verify the specific package type and revision level against the latest Texas Instruments datasheet before procurement. Confirm that the fixed I2C address matches system requirements, as it differs from the standard PCA9554 variant. Ensure software compatibility regarding register enhancements compared to legacy PCF8574 series components.

I/o Expanders Selection Notes

Select this component when 8-bit GPIO expansion is required over an I2C bus with 5-V tolerant inputs. Consider the SSOP-16 package constraints for board space. Verify that the operating voltage range of 2.3 V to 5.5 V aligns with the system supply. Account for the specific I2C address assigned by hardware pins A0-A2 to prevent bus conflicts.

I/o Expanders Part Context

The PCA9554ADB belongs to the PCA9554A family, which enhances the NXP Semiconductors I2C-bus I/O expander series. It shares pin-to-pin and I2C address compatibility with the PCF8574A but requires software adjustments due to added features like polarity inversion and higher drive capability. It is distinct from the PCA9554 only by its fixed I2C address, allowing mixed usage on the same bus.

I/o Expanders Replacement Considerations

TCA9554APWR is a recommended replacement offering similar functionality in a TSSOP-16 package.