AM6422: External Analog Reference for ADC0

Hello Alex, 

Thank you for the query.

Help me understand what measurements you doing and the use case to reduce the range.

Regards,

Sreenivasa

Hello Sreenivasa,

Thanks for your reply.

I want to monitor supply voltage and external temperature sensor. I need analog values in a very low frequency (about 1kHz). In sum, i will use 3 chanels of the ADC. I have very pecise 1,225V reference voltage on board which i would like to use as reference of AM6422.

Regards,

Alex

Hello Alex, 

Thank you.

Please refer updated information. The 1.25V Vrefp input seems to be out of the allowed voltage range for Positive Reference Voltage,
ADC0_VREFP 1.71 1.89. See below highlighted text.

Regards,

Sreenivasa

Hello Alex, 

Please note the updates to the above note on the allowed ADC input reference range.

You mentioned that you plan to measure supply voltage and temperature.

Please be aware that the ADC inputs are not fail-safe.

In case you are measuring the supply voltage that is available before the SOC ADC supplies ramp, the supply may be required to be switched.

Regards

Sreenivasa

Hi Sreenivas,

this is why i asked.

I do not understand why there is an reference input on the device, when it is not allowed to use another voltange then supply of analog part. this is why i tested it and it works, so i think the reasen could be perhaps lower AC-performance.

In previous ADC-projects with other controllers, i used stable and low noise analog supply voltage to create a lower, more precise analog reference.

Regards,

Alex