Texas Instruments PCF8574ADWE4, I²C 8-bit I/O expander, 100 kHz clock, 2.5V to 6V supply, push-pull outputs, interrupt output, 16-SOIC, -40°C to 85°C.
| Parameter | Value |
|---|---|
| Output type | Push-Pull |
| Mounting | Surface Mount |
| Supply voltage | 2.5V ~ 6V |
| Current - output source (Sink) | 1mA, 25mA |
| Clock frequency | 100 kHz |
| Interface | I²C |
| Operating temperature | -40°C~85°C |
| Package | Tube |
| Features | POR |
| Number of i (O) | 8 |
| Case | 16-SOIC (0.295\", 7.50mm Width) |
| Interrupt output | Yes |
The push-pull outputs can sink 25 mA per pin — enough to drive an LED or a small relay directly — but source current is limited to 1 mA, so pulling a line high into a heavy load needs an external pull-up or a buffer. An interrupt output (active-low, open-drain) signals the host when any input changes state, reducing polling overhead.
That means no end-of-life notice, no last-time-buy deadline, and no forced redesign for the foreseeable future.
The PCF8574 and PCF8574A are functionally identical 8-bit I²C I/O expanders. The difference is the I²C slave address range: the PCF8574 uses addresses 0x20–0x27, while the PCF8574A uses 0x38–0x3F. This allows up to 16 expanders on the same bus without address conflict.
Yes, the PCF8574ADWE4 operates from 2.5V to 6V, so it works on a 5V supply without any issue.