LT1072CN8 Datasheet, PDF (9/16 Pages) Linear Technology – 1.25A High Efficiency Switching Regulator

U
LT1072 OPERATIO
Synchronizing with Bipolar Transistor
V_IN
LT1072
GND
V_C
R3
2N2369
C1
C2
68pF ^R1
3k
R2
2.2k
FROM 5V
LOGIC
LT1072 • OP01
LT1072
Synchronizing with MOS Transistor
V_IN
LT1072
GND
V_C
R3
VN2222*
D1
1N4158
C2
200pF
C1
R2
D2
FROM 5V
2.2k
1N4158
LOGIC
*SILICONIX OR EQUIVALENT
LT1072 • OP02
TYPICAL APPLICATIO S
V_IN
C5 ⁺
5V
25µF*
Totally Isolated Converter
OPTIONAL
OUTPUT FILTER
R4
2.7k
V_IN
V_SW
1:N ^D1
C3
0.47µF
+
N
N⁺
C1
200µF
C4
200µF
L1
15V ^10µH
+ _C5
COM
200µF
L2
–15V ^10µH
+
C6
200µF
LT1072
GND
V_C ^FB
C2
0.01µF
N = 0.875 = 7:8
FOR V_OUT = 15V
500Ω
R2
5k
*REQUIRED IF INPUT LEADS ≥ 2”
≈ 16V
V_IN
0
t_OFF
t_ON
SWITCH VOLTAGE
V_OUT + V_f (V_f = DIODE FORWARD VOLTAGE)
0V
SECONDARY VOLTAGE
N • V_IN
LT1072 • TA03
1072fc
9