LT1
170/LT1
171/LT1172
TYPICAL PERFOR A CE CHARACTERISTICS
Idle Supply Current vs
Temperature
11
10
IDLE SUPPLY CURRENT (mA)
V
C
= 0.6V
FEEDBACK VOLTAGE (mV)
9
8
7
6
5
4
3
2
1
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
1170/1/2 G13
SWITCH CURRENT (µA)
V
SUPPLY
= 60V
V
SUPPLY
= 3V
Shutdown Thresholds
400
350
CURRENT (OUT OF V
C
PIN)
– 400
– 350
– 300
– 250
– 200
VOLTAGE
150
100
50
V
C
VOLTAGE IS REDUCED UNTIL
REGULATOR CURRENT DROPS
BELOW 300µA
0
– 150
–100
– 50
TIME (µs)
250
200
1.8
1.6
1.4
1.2
1.0
–75 –50 –25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (°C)
1170/1/2 G17
FLYBACK VOLTAGE (V)
V
C
PIN VOLTAGE (mV)
300
0
–75 –50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
1170/1/2 G16
Transconductance of Error
Amplifier
7000
6000
θ
–30
0
30
g
m
60
90
120
150
180
1k
10k
1M
100k
FREQUENCY (Hz)
210
10M
1170/1/2 G19
TRANSCONDUCTANCE (µmho)
5000
4000
3000
2000
1000
0
FEEDBACK PIN VOLTAGE (mV)
–1000
6
U W
Feedback Pin Clamp Voltage
500
450
400
350
300
250
200
150
100
50
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FEEDBACK CURRENT (mA)
1170/1/2 G14
Switch “Off” Characteristics
1000
900
800
–55°C
25°C
150°C
700
600
500 V
SUPPLY
= 3V
400
300
200
100
0
0
V
SUPPLY
= 15V
V
SUPPLY
= 40V
V
SUPPLY
= 55V
10 20 30 40 50 60 70 80 90 100
SWITCH VOLTAGE (V)
1170/1/2 G15
Flyback Blanking Time
2.2
2.0
V
C
PIN CURRENT (µA)
Isolated Mode Flyback
Reference Voltage
23
22
21
20
19
18
17
16
15
–75 –50 –25
R
FB
= 10k
R
FB
= 1k
R
FB
= 500Ω
25 50 75 100 125 150
TEMPERATURE (°C)
0
1170/1/2 G18
Normal/Flyback Mode Threshold on
Feedback Pin
500
490
480
470
460
450
440
430
420
410
400
–50 –25
0
FEEDBACK PIN CURRENT
(AT THRESHOLD)
FEEDBACK PIN VOLTAGE
(AT THRESHOLD)
–24
–22
FEEDBACK PIN CURRENT (µA)
–20
–18
–16
–14
–12
–10
–8
–6
–4
25 50 75 100 125 150
TEMPERATURE (°C)
1170/1/2 G20
PHASE (DEG)
LINER [ LINEAR TECHNOLOGY ]
