Model 4200A-SCS Parameter Analyzer Reference Manual
Section 13: LPT library function reference
4200A-901-01 Rev. C / February 2017
13-145
pulse_load
This command sets the output impedance for the load (DUT).
Usage
int pulse_load(int
instr_id
, long
chan
, double
load
);
instr_id
The instrument identification code of the pulse card, such as VPU1 or VPU2
chan
Channel number of the pulse card:
1
or
2
load
Output impedance (in ohms): 1 to 10e6 (default 50)
Pulse modes
Standard, Full Arb, Segment Arb
Details
DUT impedance can be independently set for each pulse card channel. The DUT impedance can be
set from 1 Ω to 10 MΩ, depending on the programmed pulse high and low values.
Maximum power transfer is achieved when the DUT impedance matches the output impedance of the
pulse card. For example, if the DUT impedance is set to 1 MΩ, the voltage output settings will change
to account for the higher DUT impedance, ensuring that the voltage at the DUT will not be double the
voltage setting (caused by reflection due to load mismatching).
The purpose of setting the DUT load to a value other than 50 Ω is to simplify the calculation of the
output levels. For example, if the DUT load is set to 50 Ω, but the actual DUT load has a high
impedance of 1 MΩ, setting a voltage level of 2 V will result in a 4 V pulse at the DUT. Setting the
DUT load to 1 MΩ will permit the set voltage to match the actual voltage, so setting a 2 V level will
result in a 2 V pulse, with the pulse card taking the DUT impedance into account.
Example
pulse_load(VPU1, 1, 100)
Sets the output impedance of pulse card channel 1 to 100 Ω.
Also see
None
