# ESD array power and protect from same source

I am working on incorporating ESD protection for flash circuitry on ESP32 custom PCB board, and after initial research, ordered an ESD Array (CM1293A-04SO) from digikey with datasheet here

Attached in the circuit diagram below, showing

• USB Rx, Tx, and Pin 0 connecting to 3 channels of the array, and
• Handmarked "Flash_3.3V" netlabel connecting to Channel 3,4 via Blue Line and connecting to IC Power Source at pin 5 via Red Line.

My questions is regarding the power line (2 options drawn in red and blue), and I am wondering if the array can simulataneously power and protect the incoming power from USB line.

I got this idea from another protection array RClamp7522T with datasheet link here. with similar electrical circuit ( but higher pricing, with lower capacitance, higher protection range for ESD, a shared zener diode, and no power source), where it shows on page 7, that IC can protect power circuit as well. Please see screenshot

• I came across the post mentioned below where someone said ESD pulse can be handled by the bypass capacitors which I have in place. I guess, I need to build the circuit and test it out myself. electronics.stackexchange.com/questions/401699/… Jan 2, 2021 at 0:20
• Yes, either will protect. Jan 2, 2021 at 2:46

So I learned and answered my original Questions after some R&D :

ESD protection is different for

• Digital I/O Lines
• Power Lines

Digital IO Lines :

• as they are usually one way Industry preference if for high preference for unidirectional TVS
• Additionally CMOS inputs are VERY sensitive to negative spikes, and unidirectional TVS have IV characteristic curves where cutoff/forward bias for negative spike is MUCH less than Positive spike
• Power Dissipation Requirement is low, order of milliWatts

Power Lines :

• Require Large Power Dissipiation (watts)
• Industry practise is to use bidirectional TVS's

The above IC being used and tested, and even thoough working, WILL not provide rectification for power, as it is rated ONLY for ~250milliWatts.

Going to replace :-

1. Digitial IO Protection with : Applied-Power-AU3321D5_C393856 @ LCSC $0.03 2. Power Line Protection with : MMBZ5V6ALT1 @ Digikey (0.10), and LCSC @$0.03 with 40Watts sinking capability.