What is the value of the input impedance of the OP-AMP inside the STM32U535 in follower mode?

[Aurelien1]

Hi

The DataSheet doesn"t give the input impedance of internal OP-AMP in follower mode.

The only value is for PGA mode.

There is a similar question about STM32U575 on the forum but not answer...

 

Thanks for your help

 

have a good day.

 

Aurélien

[MasterT]

Usually CMOS opamp has close to unlimited input impedance, 1GOhm - 1TOhm.  Since input routed via common GPIO pin leakage current likely to derate input impedance to lower value, something in ~100 MOHm range, and affected by temperature of the IC.

[Aurelien1]

Hi,

I need to know the "exact" value. My input is a kind of current/voltage converter I need to know if STM32U535 can be used alone or if an external AOP is mandatory.

Thermal part  will be also checked.

I must take care of pcb area and ultra-low power.

Have a good day.

 

Aurélien

[Billy OWEN]

Hi @Aurelien1 

 

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Regards,

Billy