My sincerest apologies if this is a duplicate question. Disclaimer: I did my best to crawl through the forums to see if I could find the answer and after an hour, I am lost. With that out of the way, below is my issue:

I am looking to determine what the below symbols are for a battery protection design using ti's BQ27750EVM board. The picture of the symbols (circled in red) in the schematic is below:

Schematic Diagram

And below is a picture of where, on the development board, the E2 and E3 components are:

Picture of EVM board I2C connector for E2 and E3 symbols

These pictures can be found at the following link: https://www.ti.com/tool/BQ27750EVM-837

Any help on this issue would be greatly appreciated.



1 Answer 1


The "part" near the top is not actually a distinct part, but rather the multiple pins of the FET. From the FET datasheet, you see that the FET is a 5x2 BGA package; source 1 is on A1, B1, D1, and E1 while source 2 is on A2, B2, D2, E2:

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The other parts (E1,E2...) are spark gaps to handle severe transients. They're a low cost approach to solving the same problem that a board-mounted gas discharge tube would.


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