Datasheet

15
LT1681
1681f
C1: MURATA ERIE GHM3045X7R222K-GC C2, C3, C4: VITRAMON VJ1825Y155MXB C5 TO C8: 330µF 10V KEMET T510X337K010AS
OR 330µF 6.3V KEMET T520D337M006AS
ISO1: FAIRCHILD MOC207 L1: COILCRAFT DO1608C-472 L2: PANASONIC ETQPAF4R8HFA L3: COILCRAFT DO1608C-105 Q1, Q3: SILICONIX Si4486EY Q5, Q6, Q14,Q15: FAIRCHILD FDS6680A T1: MIDCOM 31267R OR COILTRONICS CTX02-14675
(FUNCTIONAL INSULATION) OR MIDCOM 31322R (BASIC INSULATION)
T2: MIDCOM 31264R
(FUNCTIONAL INSULATION) OR MIDCOM 31323R (BASIC INSULATION)
V
CC
14
2 1
5
1µF 82pF
OVLO SHDN
1.24k
73.2k 20k
24k
10k
267k
0.25W
68µF
20V
56k
5V
REF
6
F
SET
4700pF
8
SS
10 15
BAS21
BAT54
T2
S
S
BAS21
BAT54
BAT54
ZVN3310F
9
V
C
PGND
12
I
MAX
V
FB
374
THERM
LT1681SW
SYNC SGND
52.3k
10Ω
1k
3k
1k
3.3k
100Ω
0.25W
10k
2k
FZT690B
4.7µF
0.22µF
S
MMBZ5240BLT1 10V
1
3.3Ω
10k
5V
REF
ISO1
MOC207
7
143
3 1
4 6
5
14 15
6 5
82
3300pF
4700pF
0.1µF
5V
REF
13
SG
+
0.1µF
1nF
11
SENSE
16
BG
18
BSTREF
19
TG
17 20
BAS21
0.1µF
L3 1mH
BLKSENS
MMBZ5245LT1
15V
V
BST
220pF
C4 1.5µF 100V
C3 1.5µF 100V
L1
4.7µH
0.022µF
1000pF
••
SYNC V
FB
OVPIN
MARGIN
I
COMP
V
DD
OPTODRV V
AUX
0.1µF
12
I
SNS
11
I
SNSGND
16
FG
2
CG
PGND GND
LTC1698
PWRGD
6
8 9 7 13
1.24k
1%
976Ω
4.22k 1%
1043
V
COMP
1681 F07
3.01k
1k
0.1µF
MBR0530
0.030Ω
1/2W
1 2 5 4
Q3
NC
1000pF
100V
2.2nF
250V
1nF
100V
Q5, Q6
FDS6680A
×2
Q14, Q15 FDS6680A ×2
MURS120T3
MURS120T3
10Ω
6
11 10
8 7 9
12
•
•••
3
Q1
T1
10Ω
MMBT3906LT1
MMBT3906LT1
V
IN
+
V
IN
–
C2 1.5µF 100V
V
OUT
+
V
OUT
–
S
C5 TO C8 330µF
10V ×4
10Ω
0.25W
10Ω
0.25W
4.7Ω
L2
4.8µH
330pF
+
MMBT3906LT1
MMBZ5248B-7 18V
Figure 7. 36V-72V DC in to 5V/10A Isolated Synchronous Forward Converter
TYPICAL APPLICATIO S
U