Section 5: Pulse measure and pulse generator units
Model 4200A-SCS Parameter Analyzer Reference Manual
5-62
4200A-901-01 Rev. C / February 2017
Example 1, showing a 5 V pulse into a 50 Ω DUT load.
V = I * R (Ohm’s Law)
Calculate the current, I
DUT
:
I
DUT
= V
TOTAL
/R
TOTAL
= V
INT
/ (50 Ω + 50 Ω) = 10 V / 100 Ω = 0.1 A
Note that the internal voltage, V
INT
, is 2 times the requested 5 V, so that V
DUT
= 5 V. The 2 times
multiplier is the default case, where:
R
DUT
= Pulse Load = 50
Ω
Pulse load is a channel-based parameter that allows the pulse generator to calculate the value of the
multiplier to source the proper voltage to provide the desired pulse level for the supplied value of the
pulse load. Whenever the value for pulse load does not equal the actual DUT resistance, the voltage
across the DUT will not match the programmed voltage level.
Calculate V
DUT
:
V
DUT
= I
DUT
* R
DUT
= 0.1 A *
50 Ω = 5 V.
Example 2: High resistance DUT
A high resistance DUT is shown in the following figure.
R
DUT
1 MΩ
Pulse V
high
5 V
Pulse V
low
0 V
Pulse load
50 Ω
Figure 199
: 5 V pulse into a 1 MΩ DUT load
This example shows
a 5 V pulse into a 1 MΩ DUT load.
Calculate the current, I
DUT
:
I
DUT
= V
TOTAL
/R
TOTAL
= V
INT
/ (50 Ω + 1 MΩ) = 10 V / 1.6 Ω = 9.9995E-6 A
≈
10
µ
A.
Calculate V
DUT
:
V
DUT
= I
DUT
* R
DUT
= 10
µ
A * 1E6 Ω
≈ 10 V.
V
DUT
≈ 10 V because the pulse load = 50 Ω, but R
DUT
= 1 MΩ. The pulse generator calculates the
output voltage based on the pulse load, and uses a 2 times multiplier to determine V
INT
= 10 V. Since
the pulse generator cannot measure the output voltage or DUT load, this example results with a V
DUT
that 2 times the programmed level.
