Kinetis KL series differential ADC

peterkisfaludi — Thu, 21 Sep 2017 15:53:13 GMT

Hi NXP,

My question is about the differential ADC built into KL series (specifically, I am interested in KL46 and KL28, but I guess the question is generic enough).

Is the differential ADC implemented as doing 2 single ended measurements very quickly after each other, or is there a real differential amplifier somewhere in hardware?

If it is a true differential measurement, then I wonder why the max and min input to the pins is specified as Vss ... 3.6V. In differential measurements, the benefit (among others) is that there can be a DC offset on both of the differential inputs, but it will measure the difference.

Thank you and Best Regards,

Peter

Re: Kinetis KL series differential ADC

miduo — Tue, 26 Sep 2017 08:27:19 GMT

Hi,

Understood your concerning. As we know that most differential A2Ds require a true differential input to achieve the best performance. However the difference of two input of Kinetis L is limited between VREFH and VREFL. The each input voltage should limited in VDD-VSS per the data sheet. I would double check this issue and response soon.

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Kinetis KL series differential ADC

Re: Kinetis KL series differential ADC