The capacitance on the BIAS pin helps the IEC ESD performance on the DM_IN and DP_IN pins.

When a short-to-battery on DP_IN, DM_IN, BUS, or both occurs, high voltage can be seen on the BIAS pin. Place a 2.2-µF, 50-V, X7R, 0805, low-ESR ceramic capacitor close to the BIAS pin. The whole current path from BIAS to GND must be as short as possible. Additionally, use a 5.1-kΩ discharge resistor from BIAS to BUS.