LT1304/LT1304-3.3/LT1304-5
W
BLOCK DIAGRA S
V
IN
V
OUT
L1
+
+
D1
C1
C2
V
IN
LB0
SW
2
3
4
1.5V
UNDERVOLTAGE
LOCKOUT
36mV
LBI
1
+
+
–
R1
7.2Ω
R2
1k
A2
–
A3
1.17V
BIAS
~1V
Q3
OFF
R3
R4
FB
1k
8
–
TIMERS
ENABLE
Q1
×200
6µs ON
A1
Q2
×1
1.5µs OFF
+
DRIVER
1.24V
V
REF
SHUTDOWN
SHDN
7
I
GND
LIM
6
5
1304 F01
Figure 1. LT1304 Block Diagram. Independent Low-Battery Detector A3 Remains Alive When Device Is in Shutdown
V
IN
3
LBI
1
LB0
2
SW
4
1.5V
UNDERVOLTAGE
LOCKOUT
36mV
SENSE
8
+
+
–
R1
7.2Ω
R2
1k
A2
–
A3
1.17V
BIAS
~1V
Q3
OFF
590k
R1
1k
–
TIMERS
ENABLE
Q1
×200
6µs ON
A1
Q2
×1
1.5µs OFF
+
DRIVER
1.24V
V
REF
SHUTDOWN
SHDN
7
I
GND
LIM
6
5
1304 F02
R1 = 355k (LT1304-3.3), 195k (LT1304-5)
Figure 2. LT1304-3.3/LT1304-5 Block Diagram
5