Datasheet

Loop Characteristics
2-7
Test Setup and Results
2.7 Loop Characteristics
The loop gain and phase for a 5.0-V input and a 3.0-A load is shown in
Figure 2–8. The loop crossover frequency is approximately 30 kHz, and the
phase margin is approximately 75
°
. Figure 2–9 shows the loop response using
the alternate compensation described in Section 1.3.5 Improving Transient
Response. With the alternate feedback compensation, the loop crossover
frequency is approximately 75 kHz, and the phase margin is approximately
72°.
Figure 2–8. Improved Loop Gain and Phase
Phase
–20
0
20
40
60
100 1 k 10 k 100 k 1 M
–45
0
45
90
135
Gain
f – Frequency – Hz
Gain – dB
Phase – Degrees
T
A
= 25°C
V
I
= 5 V
Figure 2–9. Measured Loop Gain and Phase for Alternate Compensation
Phase
–20
0
20
40
60
100 1 k 10 k 100 k 1 M
–45
0
45
90
135
Gain
f – Frequency – Hz
Gain – dB
Phase – Degrees
T
A
= 25°C
V
I
= 5 V