Section 5: Pulse measure and pulse generator units Model 4200A-SCS Parameter Analyzer Reference Manual5-50 4200A-901-01 Rev. C / February 2017Step 3. Is the pulse level correct for each channel?1. If the pulse level is not correct for each channel, enable load-line effect compensation (LLEC). Tocompensate for the IR drop effect, the LLEC algorithm applies multiple pulses at each sweepstep; make sure that the DUT behavior is not adversely affected by the LLEC approach. SeeControlling LLEC from an ITM (on page 5-39, on page 5-40).2. Run the test again and compare results. If the results match the test settings, the issue was thelack of LLEC.The load-line effect can reduce the voltage level at the DUT terminal when current is flowing. SeeLoad-line effect compensation (LLEC) for the PMU (on page 5-34).Refer to Step 4. Is the pulse I-V curve suspect? (on page 5-50) for examples with LLEC disabled andenabled.Step 4. Is the pulse I-V curve suspect?If the waveform has a good shape (Step 2. Verify the pulse shape), and the pulse level is correct(Step 3. Is the pulse level correct for each channel?), but the pulse I-V curve is suspect, perform thesteps below.In this procedure, you set test parameters to provide boundaries for the test envelope. When load-lineeffect compensation (LLEC) is disabled, the source voltage must be bounded.LLEC may not respond properly for a high-gain transistor (for example, a compound semiconductor-based amplifier or power transistor).If the pulse I-V curve is suspect:1. Disable the load line for the gate and drain in the Key Parameters. For an ITM, see Load-lineeffect compensation (on page 5-34).2. Choose the maximum voltage for the selected source range. For example, many high powertransistors require fairly high voltages and currents, so the PMU 40 V source range is common.3. Set the thresholds in the All Parameters pane (see next figure and PMU - all terminal parameters(on page 6-70) for more detail). Enter the maximum voltage for the DUT. For a transistor, set theThresholdVoltDrain voltage for the maximum voltage for the drain.
