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Original question:

JFE2140: OPA892

JFE2140: JFE2140 gate leakage

J Scott Merritt
Prodigy 70 points
Part Number: JFE2140

Tool/software:

I noticed distortion in some simulations with the JFE2140 and narrowed it down to an unexpectedly large gate leakage current whenever the drain to gate voltage grows above 10V.  The following leakage-test uses the TI PSpice model for the JFE2140 imported into LTSpice.  Is the model accurately reflecting the type of leakage current that can be expected ?  Do the protection diodes need to be connected/biased to reduce leakage ?  I note that simulations using models for LS844 and 2SK389BL do not indicate nearly that much leakage.  Thanks !  Scott.

  • 0
    Prodigy 70 points

    Sorry, the forum shrunk the screen shot.  Leakage current (through R2) hits about 115uA when the Drain to Gate voltage is 32 volts, then drops to a plateau of 39 nA whenever the Drain to Gate voltage is below about 10.4 volts.

  • +1 in reply to J Scott Merritt
    TI__Mastermind 22580 points

    Hi Scott, 

    No the leakage current is not modeled to represent the actual gate leakage past 10V. The curve in the datasheet is what you would expect for gate leakage and is the measured data. Ti models our devices as behavior models and not exact replicas of the device.

    For example the input offset voltage is not modeled. We released one model that can be used in many various configurations as opposed to a model that was in a diff pair config that would model the input offset voltage. Each will have identical Vgs in Tina but could be user modified if needed.  

    The diode in the model is modeling Figure 6-6 which is the IG leakage after 10V for JFE2140 device. This model is intended to show the usability of the device up to 10V only due to limitations in the tool and modeling Figure 6-6. The current in the simulation is much higher at 10V shown below. The measured values are what you would expect from the real device shown in Figure 6-6 above. Note that the leakage current takes off in the measured values as well, however due to limitations of spice the model does not accurately reflect the device measurements. 

    Model behavior

    Best Regards, 

    Chris Featherstone