9
LT1681
1681f
BLOCK DIAGRA
W
–
+
–
+
–
+
–
+
–
+
–
+
–
+
350mV
ERROR AMP
5V
REF
R
SQ
R
S
225mV
Q
10µA
S
Q
T
PHASE
DETECT
NOL
LOGIC
f = ×2
×12
20
19
18
16
13
V
BST
TG
BSTREF
BG
SG
15
PWRGND
17
BLKSENS
–
+
1.25V
1.25V
1.25V
1.25V
REFERENCE
GENERATOR
×4
UVL
(<8V)
I
LIM
14
V
CC
6
FSET
7
SYNC
10
V
C
11
SENSE
12
I
MAX
9
V
FB
1
SHDN
3
THERM
5
5V
REF
2
OVLO
4
SGND
8
SS
1681 BD
