R_PROG on LTC4425 is too low

open-ephys / commutators

Active coaxial commutator for electrophysiology

https://open-ephys.github.io/commutator-docs/

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Closed jonnew closed 11 months ago

jonnew commented 1 year ago

The PROG pin sets the maximum super capacitor charge current supplied by LTC4425. With its current value of 500 Ohms, we get a max current of

I = 1000 * 1V/500 = 2A

which is out of spec for USB2.0. This resistor should be replaced with a 2kOhm to limit current to 500 mA.

jonnew commented 11 months ago

Fixed in 6b259801f10eb22fa83777e8f2608b9c3601239d