lt1271 Linear Technology Corporation, lt1271 Datasheet - Page 4

• Manufacturer Part Number: lt1271
• Description: 4a High Efficiency Switching Regulators
• Manufacturer: Linear Technology Corporation

LT1271/LT1269
TYPICAL PERFOR
TYPICAL
4
12
6
0
9
3
A
Switch Current Limit vs Duty Cycle
0
PPLICATI
10 20 30
–55 C
125 C
DUTY CYCLE (%)
40
OPTIONAL
INTPUT
FILTER
W
L3
50 60 70 80 90 100
O
A
–12V
U
V
25 C
U
IN
CE
S
200 F
C4*
1271/69 G01
Negative-to-Positive Buck-Boost Converter
C
+
HARA TERISTICS
GND
C
LT1271
V
IN
V
C
100 H
R3
2.2k
L1**
V
SW
C1
0.22 F
FB
R2
1.24k
** COILTRONICS CTX100-2-52
MBR340
* REQUIRED IF INPUT LEADS 2"
200 F
D1
C2
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
+
0
Switch Saturation Voltage
T
2N3906
J
= 25 C
OPTIONAL
OUTPUT
Q1
FILTER
1
L2
SWITCH CURRENT (A)
R1
11.3k
V
12V, 1.5A
2
OUT
1271/69 TA04
C3
3
4
1271/69 G02
5