4200A-Scs Power Supply Limitations - Keithley 4200A-SCS User Manual

Model 4200A-SCS Pulse Card (PGU and PMU) User's Manual

4200A-SCS power supply limitations

In some system configurations, the 4200A-SCS power supply cannot supply enough current if a test
has too many high-power instruments enabled. There may be enough instruments installed to exceed
the power supply limit if the selected test has too many channels enabled.
Clarius tracks the instruments used in a test and calculates the maximum power required and
compares it to the maximum available power. If the test requires too much power, a message is
displayed and the test will not run.
The following table and the equations below it show how the power is calculated. The maximum
power available for each instrument in the test module is used in the calculation. The 4210-SMU High
Power SMU, 4211-SMU High Power SMU, 4225-PMU Ultra-Fast Pulse Measure Unit, and 4220-PGU
High Voltage Pulse Generator draw the majority of the power in the 4200A-SCS chassis.
There are two parts to the total power supply draw. The first part is the power required for the
instruments while the 4200A-SCS is idle (on, but not testing). The second part is the power required
by the instruments taking part in the test. Note that medium power SMUs (4200-SMUs and
4201-SMUs), 4200 preamplifiers (4200-PAs), and 4210-CVU and 4215-CVU modules are not
included in the equations, as their power draw is not significant.
4200A-SCS power requirements
Instrument
High Power SMU (4210-SMU or 4211-SMU)
4225-PGU
4225-PMU
4225-RPM
10 V PGU or PMU channel*
40 V PGU or PMU channel*
Medium Power SMU (4200-SMU or 4201-SMU) Not significant
4210-CVU or 4215-CVU
* There are two channels for each PGU and PMU instrument card.
Equations to calculate power:
PowerIDLE = [(29.4 * nPGU) + (50.4 * nPMU) + (4.2 * nRPM)]
PowerTEST = [(45 * nHPSMU) + (8.4 * nC10) + (54.6 * nC40)]
PowerTOTAL = PowerIDLE + PowerTEST
PowerTOTAL = 500 maximum. If PowerTOTAL is less than or equal to 500, the test proceeds.
Where:
•
nPGU = number of 4220-PGU cards in the 4200A-SCS chassis (idle power draw)
•
nPMU = number of 4225-PMU cards in the 4200A-SCS chassis (idle power draw)
•
nRPM = number of 4225-RPM modules connected to PMUs (idle power draw)
•
nHPSMU = number of High-Power SMUs (4210-SMUs or 4211-SMUs) in the test
•
nC10 = number of 10 V PGU or PMU channels in the test
•
nC40 = number of 40 V PGU or PMU channels in the test
4200A-PMU-900-01 Rev. A December 2020
Idle power
Not significant
29.4
50.4
4.2
Not available
Not available
Not significant
Section 4: Pulse card concepts
Test power
45
Not available
Not available
Not available
8.4
54.6
Not significant
Not significant
4-5