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INA199: INA199

Ian Wang
Mastermind 30220 points

Part Number: INA199
Other Parts Discussed in Thread: INA193

Hi Sir,

Application：detect 0~500mA current

  1. Ref pin link to Gnd
  2. Power supply = 5V
  3. Rshunt = 100m ohm
  4. Output vs Current detect：has any equation ,
  5. Is output voltage possible under 2.0V ?

Thanks, Ian.

  • 0
    TI__Mastermind 33890 points

    Ian,

    1. Ref pin link to Gnd
      1. This makes it unidirectional 

    2. Power supply = 5V
      1. This is a global condition so you would not need to add PSRR to you calculation of error.  See https://training.ti.com/ti-precision-labs-current-sense-amplifiers Sections 3.1 and section 3.6
    3. Rshunt = 100m ohm
      1. Tolerance and accuracy of this value needs to be taken into account.
    4. Output vs Current detect：has any equation ,
      1. Vout = [Rshunt(include error)*(Current - IB(input bias current)) +VOS] Gain
      2. IB will change and normally is very small vs current of interest.  See figure 8 in datasheet.
      3. VOS offset voltage is a specification of the amplifier.  More detail is in the video.  Some error sources will matter more and some less.  for example PSRR will most likely not contribute any error as we expect no DC difference form the specified value.  Video will have more detail.
      4. Gain will be dependent on the version selected but the specification is done from -5mV to 5mV input and is at 1.5% for Version A and B.  And 1% gain error for Version C.

    5. Is output voltage possible under 2.0V ? 
      1. This device does not have the same issue as the INA193 family.  This device has different architecture and does not have the same voltage capabilites.