TM4C123GH6PM: tm4cgh6pm adc offset error ,Gain Error

Rajeshkumar VR

Intellectual 310 points

Part Number: TM4C123GH6PM

Tool/software:

Hi ,

How to do compensation for offset and gain error in tm4cgh6pm adc

in data sheet it mentions as offset error + or -5 lsb( (nominal),, gain error as = or - 10 lsb

since adc o/p = (adc code + offset code) * gain error factor.

it a 12 ADC , 1lsb = 3.3/ 2^12

how to get offset error compensation and gain error correction factor for these data sheet details.?

6 months ago

0 Charles Tsai 6 months ago

TI__Guru**** 191906 points

Hi,

What is shown for gain error is max +/-30LSB. Even using max, it is 30/4096=+/-0.7%. Using the typical gain error at 10LSB, this translates to 10/4096=0.2% at the max code.

The gain error is caused by inaccuracies in the reference voltage is ± 0.7 %. The gain errors will be smaller with an external reference. You can improve overall accuracy by paying more for an external reference with higher accuracy, say 0.1%. However, for TM4C123GH6PM, there is no option for external voltage reference.

0 Rajeshkumar VR 6 months ago in reply to Charles Tsai

Intellectual 310 points

Hi Charles

What value of Gain Correction factor, I need to use, according to your reply

i can understand your reply, but I am unable to frame gain correction factor from that

So, Final ADC Code = (ADC o/p code *Gain correction factor) + Offset error.

offset error is + or - 5 lsb , Gain Correction Factor =? if Gain error lsb is + or - 10 lsb means.

0 Charles Tsai 6 months ago in reply to Rajeshkumar VR

TI__Guru**** 191906 points

Hi,

I don't understand what you mean by Gain Corrector Factor. Are you looking for a register that can compensate the gain errors? If this is what you are looking for then there is no such register. This article provides decent introduction to various ADC errors.

https://www.allaboutcircuits.com/technical-articles/adc-offset-and-gain-error-specifications/

Arm-based microcontrollers

Arm-based microcontrollers forum

TM4C123GH6PM: tm4cgh6pm adc offset error ,Gain Error