Specs side by side
2 parts compared · 0 differing specs across 5 total parameters.
| Parameter | ||
|---|---|---|
| Case | DIP-16 / SOIC-16 (SSOP-20 variant) | DIP-16 / SOIC-16 (SSOP-20 variant) |
| Component Category | I/O Expanders (I2C) | I/O Expanders (I2C) |
| Market Reality | The PCF8574 is the 8-bit I2C port expander of button matrices, relay cards, LCD backpacks and a thousand hobby and industrial boards: eight quasi-bidirectional pins, an interrupt output, and three address pins - with one family quirk that fills every forum: the A suffix is the SAME chip at a DIFFERENT I2C address. The plain part answers at 0x20-0x27, the A part at 0x38-0x3F, pin for pin and function for function per both NXP and TI - and the cheap module trade ships whichever die was cheaper that month, label notwithstanding. The other half of this page is behavioral: a quasi-bidirectional port is not a normal GPIO, and its write-1-to-read law explains most "the input does not work" posts in existence. | The PCF8574 is the 8-bit I2C port expander of button matrices, relay cards, LCD backpacks and a thousand hobby and industrial boards: eight quasi-bidirectional pins, an interrupt output, and three address pins - with one family quirk that fills every forum: the A suffix is the SAME chip at a DIFFERENT I2C address. The plain part answers at 0x20-0x27, the A part at 0x38-0x3F, pin for pin and function for function per both NXP and TI - and the cheap module trade ships whichever die was cheaper that month, label notwithstanding. The other half of this page is behavioral: a quasi-bidirectional port is not a normal GPIO, and its write-1-to-read law explains most "the input does not work" posts in existence. |
| Role In Circuit | Original Reference Part | Original Reference Part |
| Sourcing Status | Active Shenzhen Spot Sourcing (24–48h) | Active Shenzhen Spot Sourcing (24–48h) |