STM32L476RG using internal PGAs with ADC in differential mode

[HBida]

Hi,

I am using the STM32L4 ADC in differential mode (PC0 and PC1), to capture the dual end output of a tuner which provide a 600 to 800KHz signal. The tuner maximum output is 2.0V PP, and the STM32L4 differential input is rated for 6.6V PP (-3.3V to +3.3V), and since i have to use the QFN48 version in future there is no possibility to adjust the VREF. So an OPA must be used to scale the amplitude.

Now the question : is there a way to use the internal PGAs of the STM32 rather than an external dual supply OPA, which is not cheap and add quite a lot of overhead to a board where realestate is at premium?

[Dvorak.Peter]

Feeding an ADC input from an external dual supply OPA is a bad idea.

The ADC input must always stay within Vcc and ground..