Datasheet

0.1 1 10 100 1000
Gain
Phase - Degrees
Crossover Frequency - kHz
-50
-40
-30
-20
-10
0
10
20
30
40
50
0
20
40
60
80
100
120
140
160
180
Phase
Gain
)A1(
Z
R
R
R
1
A
)S(
V
V
VOL
FS
10
8
10
VOL
IN
OUT
+´++
=
TPS40200-Q1
SLUS739E SEPTEMBER 2006REVISED JULY 2013
www.ti.com
Where:
Z
FS
is the parallel combination of C
7
in parallel with
the sum of R
8
and the impedance of C
8
A
VOL
is the open-loop gain of the error amplifier at
35 kHz, which is 44.6 or 33 dB
Figure 44 shows the result of the compensation. The crossover frequency is 35 kHz, and the phase margin is
45°. The response of the system is dominated by the ESR of the output capacitor and is exploited to produce an
essentially single-pole system with simple compensation.
Figure 44. Overall System Gain and Phase Response
Figure 44 also shows the phase boost that gives the system a crossover phase margin of 47°.
The bill of materials for this application is shown in Table 2. Gerber PCB layout files and additional application
information are available from the factory.
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