I have a carrier board with touchscreen and SMARC connector. The touchscreen is connected via USB hub (USB2.0 full speed)
When I connect a SMARC module with SMSC2532 USB hub controller from Microchip and zap the touchscreen with ESD 8kV air discharge, I see no problem with the touch.
When I connect a SMARC module with CY7C65642 USB hub controller and perform the same ESD test, the touch screen stops working.
I could find the ESD performance of the microchip hub which conforms to JEDEC class 3A but I cannot find any information for the CY7C65642 hub controller.
Basically CY7C65642 has internal ESD protection diodes on all I/O pins.
These diodes are capable of protecting ESD against up to 2.2KV which confirms to JEDEC class 2.
External ESD protection diodes need to be added for extended ESD protection.