BQ76952: Temperature measurement calibration issue

Dear Sir,

Please find the attachment.

1. NTC Datasheet 1%

2. Calculated Coefficient details via TI Expert : 

Here are the coefficients given for it: 
Search complete, bestmaxerr =  0.19999999999998863
bestA [A1 A2 A3 A4 A5] =  [-17995  31696 -27449  31679   1343]
bestB [B1 B2 B3 B4] =  [-1944  2666 -3440  4423]
Adc0 = 11703

3. Test Result using calculated coefficient from TI Expert.

Please Review attached test result.

Write reviewing you will conclude following test result for the range from -25 to 45 degree is acceptable for the customer . 

Test result from 45 to 60 degree measurement error is 3 degree.

Thereafter in accuracy is very large up to 85 degree. Few last reading 10 degree accuracy. 

The requirement of our customer is smooth temperature measurement from -30 to 100 degree with in accuracy of +/-2 degree.

We request you to provide coefficient which meets the customer requirement.

Thanks 

Rahul Sharma 

3632.Data Sheet ZENAC103F39HRCL351 (1)-1.pdfworkout Temperature Test report.xlsx

Hello Rahul,

Do you mind sharing your schematic? Up to 10 degrees difference in accuracy is very odd.

Best Regards,
Alexis

Dear Sir,

Please find the attached schematic.

Thanks

Rahul SharmaSS12_20A_V4.2 (R0.0)-Micro Section.sch.pdf

Hello Rahul,

Thank you for sharing it with me. Please give me some time to review your schematic.

Best Regards,
Alexis

Hello Rahul,

I noticed y'all have a 470ohm resistor (R96) before your NTC at TS1. Did you consider this resistor when doing the initial coefficient calculations? This will affect the temperature readings especially at higher temperatures.

Could you also try removing it and using the original coefficients to see if they help?

Best Regards,
Alexis