LT1072CN8 Datasheet, PDF (4/16 Pages) Linear Technology – 1.25A High Efficiency Switching Regulator

LT1072
TYPICAL PERFOR A CE CHARACTERISTICS
Switch Current Limit vs Duty Cycle
4
3
–55°C
25°C
2
125°C
1
0
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
LT1072 • TPC01
Maximum Duty Cycle
96
95
94
93
92
91
90
–75 –50 –25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (°C)
LT1072 • TPC02
Minimum Input Voltage
2.9
2.8
SWITCH CURRENT = 1.25A
2.7
2.6
SWITCH CURRENT = 0A
2.5
2.4
2.3
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
LT1072 • TPC04
Line Regulation
5
4
3
T_J = 150°C
2
1
TJ ^{= 25°C}
0 _{TJ = – 55°C}
–1
–2
–3
–4
–5
0
10 20 30 40 50 60
INPUT VOLTAGE (V)
LT1072 • TPC07
Switch Saturation Voltage
1.6
1.4
150°C
1.2
100°C
1.0
25°C
0.8
–55°C
0.6
0.4
0.2
0
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2
SWITCH CURRENT (A)
LT1072 • TPC05
Reference Voltage and Switching
Frequency vs Temperature
1.250
42
1.248
SWITCHING FREQUENCY ₄₁
1.246
40
1.244
39
1.242
38
REFERENCE VOLTAGE
1.240
37
1.238
36
1.236
35
1.234
34
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
LT1072 • TPC08
Flyback Blanking Time
2.2
2.0
1.8
1.6
1.4
1.2
1.0
–75 –50 –25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (°C)
LT1072 • TPC03
Isolated Mode Flyback Reference
Voltage
23
22
21
R_FEEDBACK = 500Ω
20
19
R_FEEDBACK = 1kΩ
18
17
R_FEEDBACK = 10kΩ
16
15
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (C°)
LT1072 • TPC06
Feedback Bias Current vs
Temperature
800
700
600
500
400
300
200
100
0
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
LT1072 • TPC09
1072fc
4