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INA181-Q1: best way to drive REF pin

Part Number: INA181-Q1
Other Parts Discussed in Thread: TL431LI-Q1, TLV9061, INA181

Hello Team,

My customer is planning to use INA181-Q1 for a low side bidirectional current sensing applications.

They are planning to drive REF pin with opamp as buffer at mid-supply, but that takes up lot of space on board and requires more discrete compoenents.

Can they use simple TL431LI-Q1 as REF driver? or using buffer opamp is preferable approach?



  • Hi Mahendra,

    there's no board space for two 0603 resistors and an OPAmp in a SOT-23 package?


  • Hey Mahendra,

    The TLV9061 is a pretty small op amp that could be used. If an op-amp and resistor divider is not desired, then the TL43LI-Q1 can definitely be used instead. Although the buffer is better in terms of generating a lower closed-loop output impedance. I may be wrong, but I think the resistor feedback needed for TL43LI-Q1 will generate some output impedance. The output impedance should be minimized as much as possible so as to not add to the internal feedback resistor of the INA181 which is 500kΩ.