wrong current measurement keithley 2602B

Hi

I have a problem with one 2602B, and it is wrong current measurement when used as voltage source of 5mA and complice set to 10mA (DUT current consumption is 1mA).

For 5V and compliance set to 10mA, SMU measures around 7uA.
For 5V and compliance set to 5mA, SMU measures the correct values of 1mA.

SMU returns no error, current is not limited, no blinking parameter

2w measurement.

SMU is connected directly to DUT Vcc without any external polarization circuit.
DUT entrance has a decoupling capacitor of 100nF between the two pins.

1mA should be measured correctly with both compliance configuration but it does not do it, could you explain why is this happening?

Tanks for quick reply. 

From data sheet of 2602B:   Maximum Load Impedance Normal Mode: 10 nF (typical). High Capacitance Mode: 50 µF (typical).

Since you have 100nF, try enabling the high capacitance mode.

Thanks. The DUT was a black box for me and the power supply gived 5 V as requested. I would like to understand the differences between 10mA compliance and 5 mA compliance configurations. How does the smu works in each case, as it is measuring different current consumptions with DUT working perfectly. 

My hunch is that the SMU control loop is destabilized by your 100nF.

And evidently the situation is worse for compliance setting of 10mA vs 5mA.

What is the measure range in each case?  Is it auto ranging or set to fixed current measure range?

Turning on high C mode should give you the consistent behavior of appx 1mA measured when forcing 5V regardless of current limit setting at 5mA or 10mA.