can we provide voltage at ADc pin when VCC is OFF

[babidesai123]

Posted on May 26, 2004 at 14:04

can we provide voltage at ADc pin when VCC is OFF

[babidesai123]

Posted on May 17, 2011 at 12:01

Hi,

i would like to know ,If the supply to uPSD323x has not been provided but ADC sesning input has been provided with voltage < 5V, In this case, whether it can damage the ADc line in long term basis?

In our application we need to sense the battery voltage & supply to controller has been derived from different source.There may be a chance where supply to controller is not present but because of battery ,ADC i/p voltage will be present.

Whether we should provide any protection in order to disconnect the ADC i/p when the supply to controller is not present?

Regards,

Purvi

[lwang]

Posted on May 17, 2011 at 12:01

I would use one of the GPIO pins and a FET to control the connection of battery voltage sensing. Without doing so, you are draining the battery 24-7.