Datasheet

SLUU166A - December 2003 − Revised February 2004
17
UCC39002 Advanced Load-Share Controller User’s Guide, HPA027A
Measuring the Module’s Unity Gain Crossover Frequency
The unity gain crossover frequency of the module was measured at maximum load exactly as shown in Figure
8. The measured results are displayed in Figure 9. Measurement shows the module has a dc gain of
approximately 65 dB, a zero at approximately 1100 Hz, one pole at 10 kHz, and a double pole at approximately
200 Hz, and the crossover frequency of the module, f
COMOD
, was measured to be 25.6 kHz:
f
COMOD
+ 25.6 kHz
LOAD
DC−DC
Module
V
IN
50W
NETWORK
ANALYZER
XFRMR
+Vout
−Vout
+Sense
−Sense
Channel
A
Channel
B
Source
Out
Figure 9. Connection Diagram for Measuring the Unity Gain Crossover Frequency of a Power Module
100 1000 10000 100000
−10
20
50
80
0
10
30
40
60
70
GAIN
vs
FREQUENCY
Frequency − Hz
Gain − dB
Figure 10. Gain-Frequency Response (PT4484 at Maximum Load)