BQ78350-R1: SLUC568"- bq78350 family Thermistor Coef Calculator

yosef r

Part Number: BQ78350-R1
Other Parts Discussed in Thread: BQ78350, BQSTUDIO

Hello,

I have some questions/ request regarding the excel file : "SLUC568"- bq78350 family Thermistor Coef Calculator.

1.The minimum temperature in this file that can be chose is -40 deg. and I need to calculate start from -55 deg. could you please advise how can I do it? (or maybe could you send me update Thermistor Coef Calculato file with this limit?)

2. Could you please refer me to document which explain how and where am I fill the "Ext Coef" in the BQ ?

3. The Calculator request the BETA Tolerance in percent of my thermistor, where can I find it? .

The thermistor data sheet shows the BETA value, but it 's in numbers and not in percent % .

Thanks !

over 2 years ago

0 Jose Couso over 2 years ago

TI__Mastermind 27321 points

Hello Yosef,

1- The minimum operating temperature is -40C (see below). TI does not guarantee functionality below -40C.

If you wish to proceed, you can edit cell F4 and changed to any temp. This will allow you to go below -40C.

2- Under Calibration - > Cell Temperature model

3- NTC thermistor datasheet should have it. It is the BETA tolerance. Please ask the manufacturer about this info.

Regards,
Jose Couso

0 yosef r over 2 years ago in reply to Jose Couso

Prodigy 10 points

Hello Jose ,

Many thanks for the fast replay!

I change the values as your advise.

The problem now is that when I try to load the new values to the BQ, it seems that the BQ has max allow value limit, and therefore it's not let me to load the new values of "a1" (request new value :-28356) and "a3"(request new value :-34015).

please find enclosed the file 78350 family Thermistor Coef Calculator for 103JG1J update to 105C to -55C.xlsx

0 Jose Couso over 2 years ago in reply to yosef r

TI__Mastermind 27321 points

Hello Yosef,

The temperature coefficients have a min and max values. See below.

As long as the values are within range you can write directly to the memory location using Advanced Comm tab in BQStudio.

Also, I am curious to see the result if you try this thermistor coefficient calculator. Note: it is for a different device, but should work. You only need to specify the pullup resistor which should be 18k for standard NTC 10k at room temp.

There's a FAQ for the tool itself. There, it is discussed common errors when using the tool.

Regards,
Jose Couso

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BQ78350-R1: SLUC568"- bq78350 family Thermistor Coef Calculator