Texas Instruments PCF8574AN 8-bit I2C I/O Expander, DIP-16

The Texas Instruments PCF8574AN is an 8-bit input/output expander designed for the two-line bidirectional I2C bus. Operating from a 2.5V to 6V supply, it provides general-purpose remote I/O expansion for most microcontroller families via the serial clock (SCL) and serial data (SDA) pins. Each of the eight quasi-bidirectional I/O ports (P0–P7) can be used as an input or output without a data direction control signal, simplifying firmware and hardware design.

At power-on, the I/Os are high, with only a current source to VCC active. An additional strong pull-up to VCC enables fast rising edges into heavily loaded outputs, switching off on the negative edge of SCL. This device features latched outputs with high current drive capability, allowing direct connection to LEDs. It also includes an open-drain interrupt output and achieves low standby current consumption of 10mA max. The I/O expander is compatible with most microcontrollers and supports a 100KHz bus frequency. It is housed in a PDIP-16 package and operates over a temperature range of -40°C to 85°C. With latch-up performance exceeding 100mA per JESD 78, Class II, this component ensures reliable operation in demanding environments.