Texas Instruments’ TCA5405 is a single-wire I/O expander with self-timed, single-wire (STSW) technology. It allows system designers to control and expand outputs to as many as five, using a single processor general purpose input/output (GPIO). The expander reduces the number of connections needed, thus eliminating 50% of the lines versus I²C, and 75% compared to an SPI bus. Easier implementation of port expansion makes it suitable for simple functions, such as chip select (CS) or enable (EN) pins, as well as complex functions like driving LEDs (<20 mA). Standby current consumption supports power-savvy, high-performance applications with 2 μA and a drive strength current of ±20 mA.