LTC1698
APPLICATIO S I FOR ATIO
W U U
U
L1
+
T1
V
V
OUT
OUT
+
1Ω
C
OUT
Q3
Q4
R
SECSEN
–
D3
R7
1
16
C
CILM
V
FG
DD
C4
LTC1698
2
3
4
5
6
15
14
13
12
11
T2
CG
SYNC
4.7µF
R
R5
CILM
R2
R1
PGND
GND
V
AUX
I
COMP
1k
1k
OPTODRV
I
SNS
0.1µF
R
K
V
I
COMP
MARGIN
SENSGND
PWRGD
OVPIN
MOC207
7
8
10
9
C
C
0.1µF
R
C
C
FB
C
K
V
FB
0.1µF
R4
1698 F09
BOLD LINES INDICATE HIGH CURRENT PATHS
Figure 9. LTC1698 Layout Diagram
L1
V
OUT1
3.3V
AT 10A
V
V
CC
BIAS
IN
36V
TO 72V
10k
V
DD
V
BOOST
CC
CMDSH-3
SYNC GBIAS
V
COMP
•
•
10pF
4.7µF
CG
FG
LT3710
L2
1.8µH
Q1
V
CSET
TG
FB
C
S
V
0.006Ω
OUT2
680pF
0.1µF
1.8V
SW
AT 10A
+
I
SNS
LTC1698
C
4700pF
3.01k
Q2
B340A
OUT2
ILCOMP BG
SS
VA
OUT
10k
180pF
0.01µF
3.3k
BGS
220Ω
SYNC
TG BG
LT3781
SG
33nF
•
•
PGND
CL
V
FB
CL
–
+
2.32k
1698 F10
OPTODRV
GND
V
V
REF
FB
+
–
V
C
C
: POSCAP, 680µF/4V
OUT2
ISOLATION
BOUNDARY
L2: SUMIDA CEP125-IR8MC-H
Q1, Q2: SILICONIX Si7440DP
Figure 10. Simplified Single Secondary Winding 3.3V and 1.8V Output Isolated DC/DC Converter
1698f
18
Linear [ Linear ]
