The TPIC1021 is the LIN (Local Interconnect Network) physical interface, which integrates the serial transceiver with wake up and protection features. The LIN bus is a single wire, bi-directional bus typically used for low-speed in-vehicle networks using baud rates between 2.4 kbps and 20 kbps. The LIN bus has two logical values: the dominant state (voltage near ground) represents a logic 0 and the recessive state (voltage near battery) and represents logic 1. In the recessive state, the LIN bus is pulled high by the TPIC1021 internal pull-up resistor (30 kΩ) and series diode, so no external pullup components are required for responder applications. Commander applications require an external pullup resistor (1 kΩ) plus a series diode.