LT1170/LT1171/LT1172
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Idle Supply Current vs
Temperature
Feedback Pin Clamp Voltage
Switch “Off” Characteristics
11
10
9
500
450
400
350
300
250
200
150
100
50
1000
900
800
700
600
500
400
300
200
100
0
V
C
= 0.6V
–55°C
V
8
SUPPLY
= 40V
V
7
V
= 60V
= 3V
SUPPLY
= 15V
25°C
SUPPLY
V
6
SUPPLY
= 3V
V
SUPPLY
150°C
V
SUPPLY
5
= 55V
4
3
2
1
0
–75 –50 –25
0
25 50 75 100 125 150
0
0.1 0.2 0.3 0.4 0.5 0.6
0.8
0
10 20 30 40 50 60
80
90 100
0.7
0.9 1.0
70
TEMPERATURE (°C)
FEEDBACK CURRENT (mA)
SWITCH VOLTAGE (V)
1170/1/2 G13
1170/1/2 G14
1170/1/2 G15
Isolated Mode Flyback
Reference Voltage
Shutdown Thresholds
Flyback Blanking Time
2.2
2.0
1.8
1.6
1.4
1.2
1.0
400
350
300
250
200
150
100
50
–400
–350
–300
–250
–200
–150
–100
–50
23
22
21
20
19
18
17
16
15
CURRENT (OUT OF V PIN)
C
R
FB
= 500Ω
R
= 1k
FB
FB
VOLTAGE
R
= 10k
V
VOLTAGE IS REDUCED UNTIL
C
REGULATOR CURRENT DROPS
BELOW 300µA
0
0
–75 –50 –25
0
25 50 75 100 125 150
100
125 150
–75 –50 –25
0
25 50 75
–75 –50 –25
0
25 50 75 100 125 150
JUNCTION TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1170/1/2 G16
1170/1/2 G18
1170/1/2 G17
Transconductance of Error
Amplifier
Normal/Flyback Mode Threshold on
Feedback Pin
–24
7000
6000
5000
4000
3000
2000
1000
0
–30
0
500
490
480
470
460
450
440
430
420
410
400
–22
–20
–18
–16
–14
–12
–10
–8
θ
30
FEEDBACK PIN VOLTAGE
(AT THRESHOLD)
60
g
m
90
120
150
180
210
FEEDBACK PIN CURRENT
(AT THRESHOLD)
–6
–1000
–4
150
1k
10k
100k
1M
10M
–50
50
100 125
–25
0
25
75
FREQUENCY (Hz)
TEMPERATURE (°C)
1170/1/2 G19
1170/1/2 G20
6
Linear [ Linear ]
