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INA223: VOUT pin minimum RL

Part Number: INA223
Other Parts Discussed in Thread: INA233

Hi~

May I know the minimum load resistance at VOUT pin?

According to datasheet, its electrical characteristics is based on RL= 10Kohm.

Thanks,

Tiger

  • Hi Tiger,

    can be estimated from figure 22 of datasheet.

    Kai
  • Hello Tiger,

    Kai is correct. Figure 22 (sometimes referred to as the "claw curve") shows how VOUT's swing-to-rail will reduce as you increase the IOUT current. In the electrical characteristics table, the swing to voltage rail specifications are based upon placing a 10 kOhm load resistor and over-driving the input differential voltage, so VIN <0 mV when measuring the "Swing to GND" specification and VIN > full-scale range when measuring the Swing to VS.

    Figure 22 "Output Voltage Swing vs Output Current" is a typical characterization data plot showing how VOUT will get further and further away from VS or GND once output current increases. Thus there is no load resistor used in this testing. Usually a controlled current (electronic load) is placed on the output and increased while measuring VOUT.

    You can learn more about this here:
    e2e.ti.com/.../703088

    If you want to know the minimum load resistance at VOUT, then you also must know what is the worst-case INA233 VOUT swing your system can tolerate. If your system can tolerate VOUT only swinging to {VS-1V} at 25C and at VS =3V, then that means you can use a resistor that will allow for 20mA output current. You calculate RL as {Vs-1V}/20mA = 2V/20mA = 100 Ohm. Keep in mind that this is assuming your system is always operating at 25C, if you have to compensate for temperature then you can refer to the other curves to understand what is the lowest resistor you can place at load.

    Hope this serves well.

    Sincerely,
    Peter Iliya
    Current Sensing Applications