Datasheet

4
LT1676
TYPICAL PERFORMANCE CHARACTERISTICS
UW
SHDN Pin Shutdown Threshold
vs Temperature
TEMPERATURE (°C)
–50
900
800
700
600
500
400
300
200
25 75
LT1676 G04
–25 0
50 100 125
SHDN PIN VOLTAGE (mV)
TEMPERATURE (°C)
–50
1.30
1.28
1.26
1.24
1.22
1.20
25 75
LT1676 G06
–25 0
50 100 125
SHDN PIN VOLTAGE (V)
UPPER THRESHOLD
LOWER THRESHOLD
SHDN PIN VOLTAGE (V)
0
SHDN PIN INPUT CURRENT (µA)
5
0
–5
–10
–15
–20
4
1676 G05
1
2
3
5
25°C
–55°C
125°C
SHDN Pin Input Current
vs Voltage
SHDN Pin Lockout Thresholds
vs Temperature
TEMPERATURE (°C)
SWITCH MINIMUM ON-TIME (ns)
600
500
400
300
200
100
0
1676 G09
–50 25 75
–25 0
50 100 125
V
IN
= 48V
R
L
= 50Ω
FB =
TEMPERATURE (°C)
SWITCHING FREQUENCY (kHz)
106
104
102
100
98
96
94
1676 G07
–50 25 75
–25 0
50 100 125
TEMPERATURE (°C)
MINIMUM SYNCHRONIZATION VOLTAGE (V)
2.25
2.00
1.75
1.50
1.25
1.00
0.75
1676 G08
–50 25 75
–25 0
50 100 125
Switching Frequency
vs Temperature
Switch Minimum On-Time
vs Temperature
Minimum Synchronization Voltage
vs Temperature
V
C
Pin Switching Threshold,
Boost Threshold, Clamp Voltage
vs Temperature
TEMPERATURE (°C)
–50
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
25 75
LT1676 G10
–25 0
50 100 125
V
C
PIN VOLTAGE (V)
CLAMP
VOLTAGE
BOOST
THRESHOLD
SWITCHING
THRESHOLD
FB PIN VOLTAGE (V)
1.0
FEEDBACK AMPLIFIER OUTPUT CURRENT (µA)
100
50
0
–50
–100
–150
1.4
1676 G11
1.1
1.2
1.3
1.5
25°C
–55°C
125°C
Error Amplifier Transconductance
vs Temperature
Feedback Amplifier Output
Current vs FB Pin Voltage
TEMPERATURE (°C)
–50
750
700
650
600
550
500
450
400
25 75
LT1676 G12
–25 0
50 100 125
TRANSCONDUCTANCE (µmho)
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