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INA241B: REF1 and REF2 resistor values

John Larkin
Prodigy 100 points
Part Number: INA241B

Tool/software:

What are the internal REF1 and REF2 resistor values? I need to estimate reference source loading.

  • 0
    Guru 286160 points

    They are matched, but an absolute value is not specified or guaranteed.

    Section 8.4.3.4 says:

    The reference pins are designed to be connected directly to supply, ground, or a low-impedance reference voltage. The reference pins can be connected together and biased using a resistor divider to achieve a custom output voltage. If the amplifier is used in this configuration, as shown in Figure 8-8, use the output as a differential signal with respect to the resistor divider voltage. Use of the amplifier output as a single-ended signal in this configuration is not recommended because the internal impedance shifts can adversely affect device performance specifications. If single-ended measurement is required, TI recommends to use an external op amp to buffer the resistor divider voltage (see Figure 8-9).

  • 0 in reply to Clemens Ladisch
    TI__Mastermind 31995 points

    Hello Valued Engineer, 

    I am looking this over and will respond shortly.

    Sincerely,

    Peter

  • 0 in reply to Peter Iliya
    TI__Mastermind 31995 points

    Hello,

    REF1 and REF2 resistors are typical 50 kΩ at +/-20% absolute value variation as Clemens referred to. The actual matching tolerance error between these two resistors is specified in the datasheet.

    Sincerely,

    Peter

  • 0 in reply to Peter Iliya
    Prodigy 100 points

    Thanks! That will save me a buffer opamp.