IC18 Reference Voltage for MAX1329 is damaged

[tprzywoz]

On my test board IC18 output is ~0.5 V (even with R85 and R86 removed). Probably it's because MAX1329 receives VREF before configuring the AVDD (default state of MAX's Internal Charge Pump is OFF)

[gkasprow]

we need to route AVDD to SHDN of reference source

[tprzywoz]

Just remember that AVDD is about 4 V.

[skuchars]

From ADR391 datasheet: I assume we will use first option? Regarding @tprzywoz last note - there is no specified maximum voltage for Shutdown Logic High and minimum is 2.4 V, and V_IN can range from 2.8 V to 15 V, so I think 4 V will be ok.

[skuchars]

@gkasprow

[gkasprow]

4V is OK, it,s within the supply range

[skuchars]