Hi Tom, here got the reply from customer on the experiment: it seems the GND is very dirty. how to deal with it? tks! 1. after replacing the inductor btw two GND with 0 Ohm, the result is the same. 2. attached is channel 7 sampling result, it is connected to GND, while it seems the result drift a lot. 3. the ref voltage during sampling has ripple of 45mV. They tried add 2.2u /0.1u cap btw REF+ and REF-, While the result is even worse. as for your questions, the Vcc2V3 relationship with TP29 is as below, it use OPA as a voltage follower. and beforeR483, R482, there are voltage follower as well, PD1_OUT is the output of AD8304. (Please visit the site to view this file)
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