Datasheet

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