TECH
NOTE
Large-Signal Frequency Response
of the 3916338 Current Source Module
PURPOSE
100% Modulation (0 – 1 A)
Cable End Load, (2.5V p-p mod signal, Idc = 500mA)
MEASUREMENT SETUP
1.2
1
0.8
Aout p-p
This ILX Lightwave Technical Note presents the bandwidth
performance of the LDC-3916338 Module when applying
large-signal modulation.
0.6
0.4
0.2
P
0
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
Frequency
1.E+05
1.E+06
1.E+07
Figure 1. 1.0 A p-p Modulation
R
100% Modulation (0 – 2 A)
Cable End Load, (5.4V p-p mod signal, Idc = 1000mA)
2.5
PROCEDURE
The test set-up measured the modulation response of two
separate modules at three different output levels - 1.0 A p-p,
2.0 A p-p, and 3.0 A p-p. The equipment was connected as
shown in Fig. 1 with the LDC-3916338 modules operating in
High-Bandwidth mode. For each output level the DC output
current from the LDC-3916338 were set to 50% of the peak
current level. The modulation input voltage on the function
generator was adjusted to achieve 100% modulation depth.
Aout p-p
2
0
1.E+00
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1.E+01
1.E+02
1.E+03
1.E+04
Frequency
1.E+05
1.E+06
1.E+07
1.E+06
1.E+07
Figure 2 2.0 A p-p Modulation
100% Modulation (0 – 3 A)
Cable End Load, (8V p-p mod signal, Idc = 1500mA)
3.5
3
2.5
Aout p-p
The test procedure above was repeated for each module
in each range. Figures 1 - 3 show the large-signal
frequency response of the LDC-3916338 modules. In all
test conditions the 3 dB point is no lower than the specified
600 kHz.
1
0.5
The resistive load was connected via a standard
CC305S Unterminated Interconnect Cable. Output voltage
measurements were made across the 1Ω resistor using the
oscilloscope.
SUMMARY
1.5
2
1.5
1
0.5
0
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
Frequency
1.E+05
Figure 3. 3.0 A p-p Modulation
800-459-9459
#TN3916-3
International inquiries call: 406-586-1244