LT1372/LT1377
TYPICAL PERFORMANCE CHARACTERISTICS
W
U
Error Amplifier Output Current
vs Feedback Pin Voltage
Shutdown Delay and Threshold
vs Temperature
Minimum Synchronization
Voltage vs Temperature
20
18
16
14
12
10
8
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
400
300
3.0
2.5
2.0
1.5
1.0
0.5
0
f
f
= 700kHz (LT1372)
= 1.4MHz (LT1377)
SYNC
SYNC
25°C
–55°C
SHUTDOWN THRESHOLD
SHUTDOWN DELAY
200
125°C
100
LT1377
LT1372
0
6
–100
–200
–300
4
2
0
75 100
–0.3
–0.2
–0.1
V
0.1
–50
50
100 125
150
–50 –25
0
25 50
125 150
–25
0
25
75
REF
TEMPERATURE (°C)
FEEDBACK PIN VOLTAGE (V)
TEMPERATURE (°C)
LT1372 • G04
LT1372 • G05
LT1372 • G06
S/S Pin Input Current
vs Voltage
Switching Frequency
Error Amplifier Transconductance
vs Temperature
vs Feedback Pin Voltage
2000
1800
1600
1400
1200
1000
800
5
110
100
90
80
70
60
50
40
30
20
10
V
IN
= 5V
∆I (V )
∆V (FB)
C
g
=
m
4
3
2
1
0
–1
–2
–3
–4
–5
600
400
200
0
–50 –25
100
125
150
–1
0
1
2
3
4
5
6
7
8
9
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FEEDBACK PIN VOLTAGE (V)
25 50
0
75
TEMPERATURE (°C)
S/S PIN VOLTAGE (V)
LT1372 • G07
LT1372 • G08
LT1372 • G09
VC Pin Threshold and High
Clamp Voltage vs Temperature
Feedback Input Current
vs Temperature
Negative Feedback Input Current
vs Temperature
0
–10
–20
–30
–40
–50
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
800
700
600
500
400
300
200
100
0
V
=V
REF
V
=V
NFR
FB
NFB
V
HIGH CLAMP
C
V
THRESHOLD
C
–50
50
125
100
–50
50
100 125
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1372 • G11
–25
0
25
75
150
–25
0
25
75
150
TEMPERATURE (°C)
TEMPERATURE (°C)
LT1372 • G10
LT1372 • G12
4
Linear [ Linear ]
