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OPA2145: Short-circuit current of OpAmp

John B
Intellectual 285 points
Part Number: OPA2145

Tool/software:

I am looking at the datasheet of OPA2145. I am wondering about the maximum output current of this OpAmp. The datasheet says "Short-circuit current" +/-20 mA. Is this the maximum current at OpAmp output ?

  • 0
    Guru 282560 points

    The short-circuit current flows when the output is trying to drive another voltage but is forced to zero. This is not really a useful value.

    Figure 6-12 shows that you should stay below 10 mA:

  • 0 in reply to Clemens Ladisch
    Intellectual 285 points

    How we can relate the maximum continuous output current to the short-circuit current ? Let's suppose an OpAmp is driving a voltage. What maximum current we can get. I notice that some data sheets only describe output current while some other only have short-circuit currents. 

  • 0 in reply to John B
    TI__Genius 12405 points

    Hi John,

    The devices are designed to withstand the short-circuit current as the maximum.  Generally, if you are driving anything low impedance (i.e. a voltage source), the device will go into current limit. The maximum "continuous output current" is the current limit value.

    This assumes the device does not go into thermal shutdown- if you load the output with a high current, the resulting power dissipation on the die can be high, and the device may go into thermal dissipation.

    It may help to discuss this with a circuit in mind - do you have a specific circuit that will help narrow this down?

    Regards,
    Mike

  • +1 in reply to John B
    Guru 282560 points

    There is no specific relationship between these values (except that the short-circuit current always is larger). The short-circuit current is measured when the output voltage drops to zero. The output current is specified for some other output voltage; the datasheet usually picks some voltage or current that it thinks is reasonable for this device.