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OPA2992: Operating supply current per amplifier

Andreas Nestler
Intellectual 350 points
Part Number: OPA2992
Other Parts Discussed in Thread: OPA2310

Hello,

the datasheet does not specify the operating supply current per channel. There is a value of 2.4mA mentioned in Feature section. I guess it is a typical value. We plan to replace another TI Opamp with the OPA2992 and supply current is critical parameter. For other devices TI specifies the supply current with typical and maximum values. Furthermore, what is the max. achievable output current.? The datasheet specifies short circuit current only (65mA). Figure 6-16 is a graph to plot the voltage drop versus load curent (sourcing) for different temperatures but basically with typical values .

Thanks im advance!

Best Regards Andreas

  • 0
    Guru 257880 points

    Section 6.7 specifies the maximum IQ as 2.84 mA (×2). (For CMOS devices, the quiescent current is the operating current.)

    To estimate the worst-case output current, compare the typical and worst-case output swing from rail specifications, and interpolate for other values.

  • 0 in reply to Clemens Ladisch
    TI__Mastermind 22250 points

    Hi Andreas,

    Clemens is correct. Section 6.7 in the Electrical Characteristics table states both the typical and maximum values expected for the device per channel. 

    We also show quiescent current vs supply current in section 6.8 Typical Characteristics here:

    To add further to Clemens, I rarely look at the short circuit current when determining the output current capability of an op amp. As you saw, Figure 6-16, 6-17, and for 5V operations 6-18 and 6-19, gives a more complete view of the op-amps typical characteristics. 

    From my experience, it's very rare that a unit will not be able to follow closely to the output voltage vs output current curve. But it can happen. A general rule of thumb is that worst case, a device will have 20% less output current than what is shown in those curves. I've never looked up how much the "best case" will bring. 

    Also if you can operate in a lower supply (5V), I'd recommend using the OPA2310, as that device was specifically designed for driving high output current. 

    Let me know if this clarifies things.

    Best Regards,

    Robert Clifton 

  • 0 in reply to Robert Clifton56
    Intellectual 350 points

    Hello Clemens, hello Robert,

    thanks for your answers. I have simply not seen the specification of supply current. So thanks for that and also regarding output current capability. I did not got the point in the first reply. From my perspective all graphs (6-16 to 6-19) are showing the typical values. I think the interpolation was regarding the used supply voltage. So I will use the 20% rule as first estimate. Thank you.

    Best Regards, Andreas N.