ESP32 Forum

Our hardware designer tied the sensor pads as shown in the pic. I think he just copied that from a schematic for one of the modules. However, this ties up 4 ADCs and I'd like to use them. Can I just remove those caps (C84 / C90) and connect to the cap pads with my adc inputs? IOW, are those connections doing anything important that I don't know about. I'm pretty sure that nothing in my app needs them connected like that. Just not sure about the OS/core functions.

Looking at the WROOM schematic it has the exact same caps and connection. But the WROOM also brings SENSOR_VP & VN to the extern pins. Can you still use the WROOM ADCs on VP and VN, but not the ADCs on CAPP and CAPN?

John A

fly135 wrote:Can I just remove those caps (C84 / C90) and connect to the cap pads with my adc inputs?
John A

Hi John,

These caps were to enable Low Noise Amplifier (LNA) functionality.
The LNA is not supported anyway, so you can safely remove the caps.
The cap pads are available as regulars ADC inputs. The same applies to existing modules where the caps are installed (e.g.ESP32-WROOM-32), if you do not mind the small capacitance (270pF) coupling the inputs.

krzychb wrote:The LNA is not supported anyway, so you can safely remove the caps.

Thanx for the info!