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OPA376-Q1 for current sense

Other Parts Discussed in Thread: OPA376-Q1, OPA333-Q1

Dear Support team

I try to suggest my cutomer OPA376-Q1 for high side current sense. 

Is it possible to make circuit using OPA376-Q1 such as high-side current sense  in 11P of OPA333-Q1 datasheet?

Regards

Tomohiro Nagasawa

  • Nagasawa-san,

    Thank you for posting your question. The engineer responsible for this device is out of the office for a few days, but will be available again near the end of the week. He will respond to this as soon as he can.
  • The high side current monitor circuit, in OPA333-Q1 datasheet page 11, works as follow:

    1- Negative Input  bias current is very small so the same current is in RG and RL. This gives Output voltage = RL/RG x (Rshunt x Load current)

    2- The op amp supply is floating so the common mode can be much higher than the supply voltage. The supply voltage is protected by the zener. The current flowing into RBIAS is the sum of both op amp supply and zener currents.

    The OPA376-Q1 can works in this configuration. The only considerations are:

    1- OPA376-Q1 supply current is around 800uA but the OPA333-Q1' s around 15uA

    2- OPA333-Q1 input bias current is more stable over temperature but the OPA367-Q1' s rises much higher above 125C