This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AMC1200 Output Current Rating

Other Parts Discussed in Thread: AMC1200

I am using the AMC1200 and was wanting to know the output drive current capability.  What is the max output current that I am able to drive under normal operation?  The absolute max rating shows a +/-10 mA to any pin except the supply pins, but the electrical characteristics shows an output short circuit current of 20 mA.  Is this rated for continuous short circuit current?

thanks,

Sam

  • Hi Sam!

    What sort of load are you looking to drive with the AMC1200?  The +/-10mA is the maximum current under normal operating conditions with the 20mA being a transient load condition.  It ultimately boils down to power dissipation in the package for a continuous short circuit condition.

  • Tom,

    I am driving an equivalent 100.9 ohm load. I could possibly hit 15.9 mA at the max sensing point. Although this could only be for a few seconds at a time, then it would normally be near 5 mA. If 10 mA is the max operating output current then we may have to scale the output load resistors up to meet the requirement plus de-rating.

    thanks,
    Sam
  • Hi again Sam!

    In most applications that I've seen, the AMC1200 output is driven into the differential input of an ADC, so there is not much loading on the output. Is this a continuous 100.9 ohm load or is that the equivalent input impedance of your back end analog to digital converter?
  • Tom,

    We have some post amplifier circuitry before the ADC. The resistance comes from an RC filter network that feeds a high impedance amplifier, so yes it would be a fixed value.

    thanks,
    Sam
  • Tom,

    How long would the 20mA transient be? Micro-seconds, milli-seconds...? Would the circuit still be able to output accurate gain during the transient?

    thanks,
  • Hi Sam,

    I'll check to see if we have any characterization data on that.  In general though, the limitation on 'how long' a device can continue to output high current is limited by temperature.  The internal temperature is going to rise and the environment it is operating in is what is going to determine how long it can sustain the current.  There are curves in the datasheet that show how performance can shift with temperature rise (see page 7 for examples).