8-bit I²C I/O expander for mixed-voltage panels
It is commonly used in industrial control panels, server motherboards, and telecom line cards where a few extra digital inputs or outputs are needed without respinning the PCB or upgrading the MCU. The I²C interface runs at up to 400 kHz, matching the fast-mode standard used by most modern microcontrollers. The push-pull output stage eliminates the need for external pull-up resistors on output pins. An interrupt output (INT) is available, allowing the host MCU to remain in a low-power sleep mode until a change on any input pin wakes it. The power-on reset (POR) feature ensures the I/O expander powers up in a known state, so the firmware does not need an explicit initialization sequence before the first read or write.
In a mixed-voltage design, the PCA9554ADW can be the bridge between a 3.3 V MCU and 5 V peripherals without extra level-shifting components.
It is surface-mount only, and the factory default shipping medium is Tube. If your pick-and-place line is set up for Tape & Reel, confirm the reel option with your distributor at quote time.