LT3579 LINER [Linear Technology], LT3579 Datasheet - Page 30

• Manufacturer Part Number: LT3579
• Description: 6A Boost/Inverting DC/DC Converter with Fault Protection
• Manufacturer: LINER [Linear Technology]

LT3579/LT3579-1
APPENDIX
The current mode zero (Z3) is a right half plane zero
which can be an issue in feedback control design, but is
manageable with proper external component selection.
Using the circuit in Figure 20 as an example, Table 8 shows
the parameters used to generate the Bode plot shown in
Figure 19.
Table 8. Bode Plot Parameters
PARAMETER
From Figure 19, the phase is –134° when the gain reaches
0dB giving a phase margin of 46°. The crossover frequency
30
C
R
V
f
C
g
g
V
R0
R1
R2
R
C
R
OSC
OUT
C
OUT
ESR
ma
mp
L
PL
IN
C
C
L
F
VALUE
2200
14.6
305
130
250
2.2
1.0
30
47
12
28
7
2
0
8
5
UNITS
μmho
mho
MHz
mΩ
kΩ
kΩ
kΩ
kΩ
μH
μF
pF
pF
pF
Ω
V
V
Application Specific
Application Specific
Application Specific
Optional/Adjustable
Optional/Adjustable
Application Specific
Application Specific
Application Specific
Not Adjustable
Not Adjustable
Not Adjustable
Not Adjustable
COMMENT
Adjustable
Adjustable
Adjustable
Adjustable
V
5V
IN
Figure 19. Bode Plot for Example Boost Converter
C
22μF
IN
140
120
100
–20
80
60
40
20
0
10
Figure 20. 5V to 12V Boost Converter
100k
86.6k
2.2μH
GAIN
L1
100
V
FAULT
SHDN
RT
SYNC GND
IN
SW1 SW2
LT3579
PHASE
1k
FREQUENCY (Hz)
CLKOUT
GATE
SS
10k
FB
VC
46° AT
8kHz
0.1μF
D1
100k
130k
3060 TA02
47pF
1M
0
–45
–90
–135
–180
–225
–270
–315
–360
8k
2.2nF
3579 F20
C
10μF
V
12V
1.7A
35791f
OUT
3
OUT