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Response to a Step Load Change

Posted: April 14th, 2011, 5:06 pm
by b02102
I apply 3.3 volts to the wireless unit under test. As the unit is tested it changes many times from standby to recieve and to transmit. When stepping from standby to transmit the current will change from 50mA to 350 mA. When it does so the Keithley will drop from 3.3 volts to about 2 volts and stay that way for about 5 ms. This breaks the digital communication link to the unit causing a non-recoverable error. Do I have some configuration issue? I have set the compliance current to max. This is a 2420 so that's 3.15 A. I have also increased the decoupling capacitance but the drop out continues. Suggestions?

Re: Response to a Step Load Change

Posted: May 6th, 2011, 1:20 pm
by Dale C
I am surprised it take that long (5msec) for the Model 2420 to respond to a load change.
The spec is about 30usec (0.03msec) for load changes.There is nothing in the spec about the amount of current or voltage as the step change.
That is what I am suspicious about.
However, the suggestion is not to use the Model 2420 but one of the 2300 series power supplies.
They were designed for the fast load change recovery time.
Check out the 2308 or maybe the 2308.