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INA296B-Q1: REF1, REF2 input current

Shinji Tsuji
Genius 15369 points

Part Number: INA296B-Q1

Hi team,

Could you please give me the REF1 and REF2 input current value in the condition below?

Test circuit is same as Figure7-5 Mid-supply voltage output in the datasheet page 18. 

Condition 1 : IN+ - IN- = 0V 

Condition 2 : IN+ - IN- = 101mV

  • VS = 5V
  • REF1 = 5V
  • REF2 = 0V
  • OUT = input to MCU
  • Ta = -40c to +150c

regards,

  • 0
    TI__Mastermind 34710 points

    Hello Shinjji,

    The INA296 datasheet and EVM user guide do not explicitly list REF1 and REF2 input current values in their electrical characteristics tables. However, based on TI E2E forum discussions, the REF pin input bias current is approximately 20µA, with a variation of about ±10µA depending on the differential sense voltage [1].  Link is below and it is at the very bottom of the post.

    For your specific conditions:

    Condition

    IN+ − IN−

    Expected REF Pin Input Current

    Condition 1

    0V

    ~20µA (typical)

    Condition 2

    101mV

    ~20µA ±10µA

    This ~20µA current flows into each REF pin (REF1 and REF2) regardless of whether they are tied together or set to different voltages (as in your mid-supply configuration with REF1=5V, REF2=0V) [1].

    Key Considerations

    • The ±10µA variation occurs as the differential input voltage changes between your two test conditions [1].
    • The EVM user guide notes that input bias current should be considered when using input filtering on the reference pins, which confirms this current is non-negligible for design purposes [2].
    • If you're driving REF1 and REF2 from low-impedance sources (directly from VS and GND as in Figure 7-5), the 20µA bias current will not meaningfully affect your reference voltages.

    Important Caveat

    The ~20µA value comes from a TI E2E community discussion rather than a formally specified datasheet parameter. I was unable to retrieve the INA296 device datasheet (SBOSA04) electrical characteristics table directly. I recommend confirming this value with TI technical support or the datasheet's electrical characteristics section if you need a guaranteed min/max specification for production design.

    Citations

    1. TI E2E Forum - INA296AEVM Different Step Responses with Different REF Voltage Setups
    2. INA296EVM User Guide (SBOU280A)

    Regards,

    Javier