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MC34708 ADC input specifications anyone ?

Question asked by Pierre Schirrer on Nov 20, 2013
Latest reply on Nov 27, 2013 by Anandkumar Balakrishnan

Hello,

 

We designed our own i.MX53 board using the MC34708 companion chip. Since this nice IC comes with an integrated ADC, we figured that we are going to use one of the channels to measure the external temperature around the CPU core. We therefore wired of thermistor to ADCVIN11.

I am trying to get hold of the ADC input specifications to try to derive the conversion formula to get the temperature from the ADC reading. The datasheet is very terse in giving information on the ADC input circuitry.

 

Does anyone have more information ?

 

I am looking at input impedance values, or current drawn by the input etc.

This is about all the data sheet gives :

 

 

Why is it giving a source impedance and not a load impedance ?

A more acurate value would be needed in order to derive the conversion value etc...

 

Thanks for your help,

 

Regards,

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