Datasheet

LT3845A
9
3845afa
BLOCK DIAGRAM
–
+
–
+
–
+
–
+
–
+
V
IN
UVLO
(<4V)
BST
UVLO
8V
REG
FEEDBACK
REFERENCE
–
+
1.231V
3.8V
REG
INTERNAL SUPPLY RAIL
V
IN
V
CC
UVLO
(<6V)
SHDN
V
REF
DRIVE
CONTROL
NOL
SWITCH
LOGIC
DRIVE
CONTROL
BURST_EN
R
B
V
C
C
SS
SENSE
–
V
FB
–
+
V
REF
+ 100mV
FAULT CONDITIONS: V
IN
UVLO
V
CC
UVLO
V
SHDN
UVLO
2µA
1V
0.5V100mV
ERROR
AMP
Burst Mode
OPERATION
SOFT-START
BURST DISABLE
C
SS
CLAMPED TO
V
REF
+ V
BE
R
SQ
OSCILLATOR
SLOPE COMP
GENERATOR
BOOST
C
BOOST
M1
TG
DRIVER DRIVER
SW
V
CC
BG
PGND
SYNC
f
SET
R
SET
SENSE
+
3845A FD
BOOSTED
SWITCH
DRIVER
CURRENT
SENSE
COMPARATOR
g
m
– +
– +
R
S
Q
–
+
110mV
REVERSE
CURRENT
INHIBIT
10mV
– +
SGND
M2
C
OUT
V
OUT
R
SENSE
D2
(OPTIONAL)
L1
D1
C
VCC
C
IN
V
IN
R
C
C
C1
R2
R1
R
A
C
SS
C
C2