How can a smart controller PAC pass an ESD contact/air test?

To enable the PAC (Power Controller Acoustic Control) to pass ESD contact discharge (up to 8kV) and air discharge (up to 15kV) tests, multi-level protection is required. Insulation gaps (air gap greater than 2mm, creepage distance greater than 4mm) must be maintained between accessible metal parts (such as the housing and interface metal shells) and internal circuitry. Non-metallic housings require an internal grounded metal shielding layer. TVS diode arrays (such as ESDLC5V0D3B) and common-mode inductors (CMZ2012A-900T) are used in interface circuits (such as USB and Ethernet ports).

In the PCB layout, sensitive circuits are kept away from discharge points and a complete ground plane is used. During testing, each accessible point is subjected to 10 positive and 10 negative discharges; the system function is not lost, and it can self-recover after performance degradation. Through design, the PAC can meet IEC61000-4-2 Level 4 (8kV contact, 15kV air) requirements, with a bit error rate of less than 10^-6 after testing.