The CBT6820 is a 20-bit bus switch with precharged outputs and Schottky undershoot protection for live insertion. It features TTL compatible inputs and outputs, a 5Ω switch connection between port A and port B, and thin shrink small outline (TSSOP). Undershoot protection is included to prevent shoot through level changes, and the device precharges the B port to a user-selectable bias voltage (BIASV) to minimize signal distortion during live insertion. It is organized as two 10-bit switches with individual enable (OE) input. When OE is low, the switch is on and port A is connected to port B. When OE is high, the switch between port A and port B is open and the B port is precharged to BIASV through the equivalent of a 10-kΩ resistor. Special clamp circuitry and Schottky diode clamps to ground are used to prevent an under voltage on the A side (Vin < GND) from causing the B side precharge voltage to drop below the ‘‘1” state.