Datasheet

4
LT1425
TYPICAL PERFORMANCE CHARACTERISTICS
UW
Feedback Amplifier Output
Current vs R
REF
Pin Voltage
R
REF
NODE VOLTAGE (V)
1.05

60
40
20
0
–20
–40
–60
–80
1.20 1.30
1425 G04
1.10 1.15
1.25 1.35 1.40
FEEDBACK AMPLIFIER OUTPUT CURRENT (µA)
25°C
125°C
–55°C
TEMPERATURE (°C)
–50

2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
25 75
1425 G06
–25 0
50 100 125
V
C
PIN VOLTAGE (V)
V
C
HIGH CLAMP
V
C
THRESHOLD
V
C
Pin Threshold and High Clamp
Voltage vs Temperature
TEMPERATURE (°C)
–50

1400
1200
1000
800
600
400
200
0
25 75
1425 G05
–25 0
50 100 125
TRANSCONDUCTANCE (µmho)
Error Amplifier Transconductance
vs Temperature (R
REF
Referred)
Switching Frequency vs
Temperature
SHDN Pin Input Current vs
Voltage
Minimum Synchronization
Voltage vs Temperature
TEMPERATURE (°C)
–50

300
295
290
285
280
275
270
265
25 75
1425 G07
–25 0
50 100 125
SWITCHING FREQUENCY (kHz)
TEMPERATURE (°C)
–50

2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
25 75
1425 G08
–25 0
50 100 125
MINIMUM SYNCHRONIZATION VOLTAGE (V
P-P
)
SHDN PIN VOLTAGE (V)
0
1
0
–1
–2
–3
–4
4
1425 G09
1
2
3
5
SHDN PIN INPUT CURRENT (µA)
T
A
= 25°C
Minimum Switch ON Time vs
Temperature
Flyback Enable Delay Time vs
Temperature
TEMPERATURE (°C)
–50

300
275
250
225
200
175
150
125
25 75
1425 G10
–25 0
50 100 125
SWITCH ON TIME (ns)
TEMPERATURE (°C)
–50

250
225
200
175
150
125
100
75
25 75
1425 G11
–25 0
50 100 125
ENABLE DELAY TIME (ns)
TEMPERATURE (°C)
–50

275
250
225
200
175
150
125
100
25 75
1425 G12
–25 0
50 100 125
ENABLE TIME (ns)
Minimum Flyback Enable Time vs
Temperature