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K60 ADC, Differential without PGA, VREFH vs VREF_OUT

Question asked by pmt on Nov 2, 2017
Latest reply on Nov 3, 2017 by xiangjun.rong

I am using the K60 16-bit ADC converters similar to what is described in AN-4568.

 

I am using this in differential mode without PGA.

 

When PGA is used it is clear that the VREF_OUT signal is required and the governing voltage reference for the measurement. However when PGA is not used [refer to Table 2, ADC16 MEASUREMENT (PGA DISABLED)] it not clear what effect VREF_OUT or VREFH play in the ADC conversion.

 

Seemingly VREF_OUT is NOT needed in differential PGA disabled mode, yet the differential input range is limited to 2400mV. But where does this come from if VREF_OUT can be disabled? What effect, if any does VREFH input play in the measurement in this mode?

 

Thanks,

PMT

 

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