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INA250: Resistor temperature coefficient

Takashi Yamaguchi
Genius 13430 points
Part Number: INA250

Hi team

I have a question about the resistor temperature coefficient.

If customer wants to calculate the resistance at 50degC with 25degC as reference temp, should customer use 10 ppm/C(Ta=0C to 125C) from the E.C table below? 

R=Rref*(T-Tref)*ppm/C+Rref

R : Resistance at temperature "T"

Rref : Resistance at reference temperature 

ppm/C : Resistor temperature coefficient

T : temperature in degrees C 

Tref : Reference temperature

For example,  Tref =25degC, Rref=4.5mohm, and T=50degC.

R=4.5mohm*(50degC-25degC)*10ppm/C+4.5mohm=4.501125mohm

Regards,

Yamaguchi

  • 0
    TI__Mastermind 34250 points

    Hi Yamaguchi,

    The equation you used is correct for this type of calculation.

    In the datasheet spec table, the resistor temperature coefficient is for the integrated shunt. I would separate the calculation into two parts, ie the shunt plus lead frame which would be 2 and 2.5mOhm respectively. The temperature drift would be 10ppm and 0.4% (typical of copper) for these two materials.

    Using the same equation for these two materials individually, we get:

    2mOhm*(1 + 25C*10ppm/C) + 2.5mOhm*(1 + 25C*0.4%) = 4.75mOhm

    Regards, Guang