Datasheet

LTC3454
6
3454fa
BLOCK DIAGRAM
LED
EN2
2
EN1
I
SET2
I
SET1
R
ISET2
R
ISET1
1
800mV
I
ISET1
LED CURRENT
SETTING AMP 1
SAFETY
ERROR AMP
FORWARD
CURRENT
LIMIT
REVERSE
CURRENT
LIMIT
AUTOZEROING
ERROR AMP
CD PWM
COMPARATOR
AB PWM
COMPARATOR
–
+
–
+
–
+
1.23V
1.23V
+
–
+
–
+
–
+
–
9
LOGIC
3.4A 275mA
UNDERVOLTAGE
LOCKOUT
UV
V
IN
2.7V TO 5.5V
OVERTEMP
PROTECTION
OT
UV
OT
BANDGAP
REFERENCE
1.23V
1MHz
OSCILLATOR
SWITCH A
V
IN
OPTIONAL
SW1 SW2
SWITCH D
SWITCH B SWITCH C
V
OUT
10 6
11
V
OUT
7
V
C
8
3
3454 BD
377k
123k
I
R
EXPOSED PAD (GND)
R
3850 I
800mV
LED CURRENT
SETTING AMP 2
–
+
I
ISET2
SHUTDOWN
4
OPTIONAL
∑
5
SOFT-
START
CLAMP
CURRENT
MIRROR
GATE
DRIVERS
AND
ANTICROSS-
CONDUCTION