Datasheet

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