Datasheet

LT1308A/LT1308B
7
1308abfb
BLOCK DIAGRAMS
Figure 2a. LT1308A/LT1308B Block Diagram (SO-8 Package)
Figure 2b. LT1308A/LT1308B Block Diagram (TSSOP Package)
–
+
–
+
–
+
–
+
–
+
+
+
Σ
COMPARATOR
RAMP
GENERATOR
R
BIAS
V
C
2V
BE
g
m
Q2
×10
Q1
FB
FB
ENABLE
*HYSTERESIS IN LT1308A ONLY
200mV
A = 3
FF
A2
A1
Q4
*
ERROR
AMPLIFIER
A4
0.03
DRIVER
SW
GND
1308 BD2a
Q3
Q
S
600kHz
OSCILLATOR
5
LBO
LBI
SHDN
SHUTDOWN
3
7
1
4
R6
40k
R5
40k
R1
(EXTERNAL)
R3
30k
R4
140k
2
V
IN
V
IN
V
IN
V
OUT
6
8
R2
(EXTERNAL)
–
+
–
+
–
+
–
+
–
+
+
+
Σ
COMPARATOR
RAMP
GENERATOR
R
BIAS
V
C
2V
BE
g
m
Q2
×10
Q1
FB
FB
ENABLE
*HYSTERESIS IN LT1308A ONLY
200mV
A = 3
FF
A2
A1
Q4
*
ERROR
AMPLIFIER
A4
0.03Ω
DRIVER
SW
GND
1308 BD2b
Q3
Q
S
600kHz
OSCILLATOR
8
SW
9
SW
LBO
LBI
SHDN
SHUTDOWN
3
13
1
4
GND
5
GND
6
GND
7
R6
40k
R5
40k
R1
(EXTERNAL)
R3
30k
R4
140k
2
V
IN
V
IN
V
IN
V
IN
V
OUT
11
12
14
R2
(EXTERNAL)
10