USB Type-C CC Smart Protection

NX20P0477 is a single-chip USB Type-C (USB-C) port overvoltage protection solution integrating a corrosion prevention algorithm from moisture. CC1/CC2 pins in the system side are protected from 28 V short to VBUS.

USB-C allows VBUS voltage to increase up to 20 V through Power delivery protocol. CC1/2 pins can be shorted to VBUS due to mechanical twisting and sliding of the connector since USB-C connector contact pins are 25 % closer to each other than a micro USB connector. Moisture or fine dust may also cause the 20 V VBUS pin to be shorted to adjacent pins.

NX20P0477 enables CC pins to be more robust in even abnormal conditions. NX20P0477 is 28 V DC tolerant on CONCC pins in connector side and quickly disconnects switches if the voltage is above overvoltage threshold, protecting CC pins in system side from high voltage.

USB PD standard requires 80 μA, 180 μA or 330 μA as Rp to detect sink device, but this Rp current accelerates USB-C connector pin corrosion when CC pins are contaminated with water, especially salt water. Furthermore, CC/PD controller may recognize this water impedance as detected sink, providing 5 V through VBUS pin, which accelerates corrosion.

NX20P0477 converts these USB standard Rp currents from CC/PD controller to ultra-low current source to prevent corrosion. NX20P0477 integrates IEC 61000-4-2 ESD protection of +6 kV contact discharge and +8 kV air discharge on CONCC1 and CONCC2, which helps to reduce external BOM cost.

NX20P0477 CONCC1 and CONCC2 pins are designed to be protected from surge voltage up to +/-40 V.

NX20P0477 is offered with 0.5 mm pitch, 9 bumps, 1.49 mm x 1.49 mm x 0.555 mm WLCSP package.”