ADC pin draws much current?

[eem2am]

Hello ,

We are using an MCP9700 temperature monitor IC and feeding its output into the ADC pin (AD4) of the SAM3N00B microcontroller.
The MCP9700 only provides a maximum of 100uA output current, so is that enough to supply the current drawn by the ADC pin, or do i need to buffer the temperature monitor IC's output voltage?

MCP9700 Temperture monitor IC
http://ww1.microchip.com/downloads/en/DeviceDoc/21942e.pdf

SAM3N00B datasheet:
http://www.atmel.com/Images/doc11011.pdf

 

[BobK]

The ADC will only draw current when a sample is being taken. So, the way to deal with high impedance sources is to add a capacitor to ground big enough to supply the needed current when the ADC is sampling, and small enough to be fully charged by the sensor between sampling. This depends, of course, on how often you are sampling.

Bob