MAXIM MAX7301 4-Wire-Interfaced 2.5V to 5.5V 20-Port 28-Port I/O Expander handbook
Datasheet
The MAX7301 is a 4-wire serial interface I/O expander chip from MAXIM Corporation. It supports 20/28 I/O ports and can be configured as open drain output, Schmitt input, Schmitt input with internal pull-up, and supports logic transition detection. The maximum operating current is 11µA, and the operating temperature range is -40℃~+125℃
