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What to do with unused opamp pins

Wouter_Movella
Associate

We want to use the STM32U585QII6Q for a new design, and I want to know what I need to do with the dedicated OPAMP VINM pins on this package. We don't want to use the OPAMPs. Do I leave these dedicated pins floating or should I connect them to GND?

I checked the 'STM32 microcontroller GPIO hardware settings and low-power consumption' application note, but it doesn't state anything about dedicated OPAMP input pins.

2 REPLIES 2
Danish1
Lead II

GND should work fine. The op-amp common-mode range is 0 to VddA, so the input multiplexer should be able to cope with anything in that range.

Personally I would put a series resistor on my pcb on the path to Vss if this is a prototype. Although you might not have thought that you need an op-amp, you might later decide it is handy for some as-yet-unknown reason.

Uwe Bonnes
Principal II

I think keep OPAMP_EN disabled and keep all unused GPIO in analog mode is the way to go.OPAMPOPAMP