Kinetis MicrocontrollersのトピックRe: K10 Series ADC Internal Reference PPM?

K10 Series ADC Internal Reference PPM?

tomekkicaj — Wed, 27 Nov 2013 14:01:42 GMT

Hello All,

I'm studying K10 Docs and I found no information as to the temp. stability of the internal 1,2V reference.

Does anyone know the PPM of the voltagere reference?

How good is the ADC in K10 ? So far I've been using Sigma Delta MCP3425 and it worked very well.

Generally ADCs built it microcontrollers (especially AVR) are crap so i wonder how it looks with K10?

Thanks and regards

Tomasz

Re: K10 Series ADC Internal Reference PPM?

Paul_Tian — Thu, 28 Nov 2013 00:32:51 GMT

Hi, Tomek

After factory trimmed, the range of VREF is 1.1584V to 1.2376V.

Hope my reply can help you.

Best Regards

Paul

Re: K10 Series ADC Internal Reference PPM?

egoodii — Thu, 28 Nov 2013 02:47:17 GMT

To use your vernacular, 'crap', at +/-3.3%

I feed VrefH with a $1 REF3030AIDBZ, at 0.2% 65ppm/C. The MAX6070B is nice too...

Re: K10 Series ADC Internal Reference PPM?

Paul_Tian — Thu, 28 Nov 2013 03:36:36 GMT

Hi, Earl

After trimmed, you can get 0.5mV accuracy. You can find VREF_TRIM register in our reference manual.

Hope my reply can help you.

Best Regards

Paul

Re: K10 Series ADC Internal Reference PPM?

tomekkicaj — Thu, 28 Nov 2013 10:16:07 GMT

Thank you guys,

MCP3425 has int. ref of 2.048V ± 0.05% , Integral Nonlinearity 10ppm FSR, Gain Error Drift of 15 ppm/°C.

The accuracy of the ref voltage is not that important to me as I calibrate the end system anyway.

My concern is the -20 to +80 temperature stability of the internal rev voltage which is not stated in the datasheet.

I wonder if I should stay with the proven MCP3425 or go for the internal ADC.
I'm measuring with 12bits 0-200mV signals at 5 samples/sec.

Regards

Tomasz

Re: K10 Series ADC Internal Reference PPM?

egoodii — Sun, 01 Dec 2013 03:09:19 GMT

OK, but then 80mV drift across the temperature span. Isn't that on the order of 500ppm/C? And what about long-term-drift?

Re: K10 Series ADC Internal Reference PPM?

egoodii — Mon, 02 Dec 2013 18:53:11 GMT

It's not clear how the MCP3425 defines 0.05% and 15ppm/C -- looks to me like over temp the total conversion error runs from +0.15% to -0.3% (figure 2-6), which is much worse than the MAX6070B.