ISL6529 Datasheet, PDF (13/19 Pages) Intersil Corporation – Dual Regulator.Synchronous Rectified Buck PWM and Linear Power Controller

ISL6529, ISL6529A
frequencies and high load current. Figure 13 shows the
results of the complete system with output capacitor and
compensation network for 45° of phase margin.
Because of the large variety of capacitors, varying ESRs and
PC board layouts, Table 1, based upon system simulations
is provided as a starting point guide to aid in the selection of
compensation networks for output capacitors values of 1µF,
10µF, 100µF and 1000µF with ESR values of 5mΩ, 30mΩ
and 100mΩ for each capacitor value. The frequencies
associated with the compensation elements are also shown
to aid in component selection.
Parallel capacitors of the same value and type can be
treated as a combination. For example three 100µF, 10mΩ
capacitors may be treated as one 300µF, 3.3mΩ capacitor.
Mixed capacitors require more attention. For example the
compensation for a 1000µF, low ESR capacitor will suffice
for a shunting 10µF, low ESR capacitor.
CAP
ESR
5mΩ
30mΩ
100mΩ
TABLE 1. COMPENSATION NETWORKS FOR LINEAR REGULATOR
OUTPUT CAPACITOR
DETAIL
1µF
10µF
100µF
Comp
Network
C16 = 10pF
R12 = 47K
C4 = 200pF
C16 = 10pF
R12 = 47K
C4 = 470pF
C16 = 10pF
R12 = 200K
C4 = 470pF
Low Fq Zero (C4 & R12)
17kHz
7.2kHz
1.7kHz
High Fq
Pole (C16 & R12)
MidbandGain R12/R5
338kHz
20dB
338kHz
20dB
80kHz
33dB
OUTPUT CAP
& ESR Zero Fq
Comp
Network
Low Fq
Zero (C4 & R12)
High Fq
Pole (C16 & R12)
Midband Gain R12/R5
32MHz
C16 = 10pF
R12 = 47K
C4 = 200pF
17kHz
338kHz
20dB
3.2MHz
C16 = 10pF
R12 = 47K
C4 = 470pF
17kHz
338kHz
20dB
320kHz
C16 = 10pF
R12 = 200K
C4 = 470pF
1.7kHz
80kHz
33dB
OUTPUT Cap
& ESR Zero Fq
Comp
Network
Low Fq
Zero (C4 & R12)
High Fq
Pole (C16 & R12)
Midband Gain R12/R5
5.3MHz
C16 = 10pF
R12 = 47K
C4 = 200pF
17kHz
338kHz
20dB
530kHz
C16 = 10pF
R12 = 47K
C4 = 470pF
17kHz
338kHz
20dB
53kHz
C16 = 10pF
-
-
-
OUTPUT Cap
& ESR Zero Fq
1.6MHz
160kHz
16kHz
1000µF
C16 = 10pF
R12 = 470K
C4 = 470pF
720Hz
34kHz
40dB
32kHz
C16 = 10pF
-
-
-
5.3kHz
C16= 10pF
-
-
-
1.6kHz
13
FN9070.5
April 12, 2005