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INA210: IC Max. operating current

MINKYUNG KIM
Expert 1250 points
Part Number: INA210

Hello team,

I'd like to know IC max. operating current of INA210 to estimate IC's power consumption.

1. Is the Iq from the datasheet used as a operating current?

2. Can (Vs * Iq) be used as IC's operating power consumption? (e.g. 3.3V * 115uA = 379.5uW)

Thank you so much!

  • 0
    TI__Mastermind 18780 points

    Minkyung,

    Thanks for using the E2E forums!

    Unlike the devices in your previous post, this is not a digital part, but an analog one. Here, the common mode of the input pins can impact the bias currents of the device, and that might affect the power rating. The test condition in the datasheet was for a common mode of 12V. You need to examine your application, and where the common mode of your signal will lie to be able to find your value of bias current. Once you know your common mode, you can look to figures 11 and 12 in the datasheet to see what your bias current will be, and use that to calculate your power consumption against your output load. 

    Again, since it sounds like you are trying to find low power options, I would also advise you to look at section 7.4.2 of the datasheet for a potential shutdown circuit option with this device. This would help save additional power in your application. 

  • 0 in reply to Carolus Andrews
    Expert 1250 points

    Hello Carolus,

    Thank you for your kind reply. I have additional questions as below.

    1. As for fig 11 and 12, it's showing input bias current. I thought it was a different parameter from the IC's operating current (=supply current = quiescent current). Which is the correct parameter for power consumption calculation?

    2. Vs * Iq is for calculating the power consumption for digital current sensor. As you told me it's different from the analog current sensor, is the power consumption equation still valid here? Or, does it go for (V+-V-)*Iq, which is a power consumption equation for general OpAmp?

    Thanks a lot!

  • 0 in reply to MINKYUNG KIM
    TI__Mastermind 18780 points

    Minkyung,

    1. Thanks for the ask for clarification here. I edited my original post, as I realized I referred to the bias currents in figures 11 and 12 as quiescent current, and that is incorrect. Sorry about that. The point I was making here is that there is additional power consumption due to these currents. Our devices operate a switching front end when the common mode of the device exceeds supply. You can see this switch in figure 11, which is referred to as the crossover point. At this point, the device draws additional current into the device to power the device, and you can see these currents are present even when V_sense = 0V. 

    2. The quiescent current will still be present in the device. The correct calculation is always (V+-V-)*Iq, but as most of our use cases are single ended, V- would be referenced to ground, and the equation would simplify to V+*Iq. 

    In spoke with our designers, and they said as a rough approximation, for total power consumption in the device, it would be (V+*Iq) + (VCM*2*Ib). This second term would account for the bias currents in the device.

  • 0 in reply to Carolus Andrews
    Expert 1250 points

    It's very clear. Thank you, Carolus!