LT3681
U W
TYPICAL PERFOR A CE CHARACTERISTICS T = 25°C unless otherwise noted.
A
Error Amp Output Current
Minimum Input Voltage
Minimum Input Voltage
4.5
4.0
3.5
3.0
100
80
6.5
6.0
5.5
5.0
60
40
20
0
–20
–40
–60
2.5
2.0
4.5
4.0
V
= 3.3V
V
= 5.0V
OUT
OUT
L = 4.7
L = 4.7
f = 800kHz
f = 800kHz
–80
1.065
0.001
0.01
0.1
LOAD CURRENT (A)
1
0.1
LOAD CURRENT (A)
10
0.001
0.01
1
10
1.165
1 .265
1.365
1.465
FB PIN VOLTAGE (V)
3681 G20
3681 G20
3681 G19
Switching Waveforms;
Burst Mode
Power Good Threshold
V Voltages
C
2.50
1.200
V
= 12V; FRONT PAGE APPLICATION
= 10mA
IN
I
LOAD
I
L
2.00
1.50
1.180
1.160
0.5A/DIV
CURRENT LIMIT CLAMP
SWITCHING THRESHOLD
V
SW
5V/DIV
1.00
0.50
0
1.140
1.120
1.100
V
OUT
10mV/DIV
PG RISING
3681 G24
–50 –25
0
25
50
75 100 125
–50 –25
0
25
50
75 100 125
2µs/DIV
TEMPERATURE (°C)
TEMPERATURE (°C)
3681 G22
3681 G23
Switching Waveforms; Transition
from Burst Mode to Full
Frequency
Switching Waveforms; Full
Frequency Continuous Operation
Power Schottky Diode Forward
Voltage vs Current
6000
5000
4000
I
L
0.5A/DIV
I
L
0.5A/DIV
V
V
RUN/SS
5V/DIV
RUN/SS
5V/DIV
3000
2000
V
V
OUT
OUT
10mV/DIV
10mV/DIV
1000
0
V
I
= 12V; FRONT PAGE APPLICATION
= 1A
V
I
= 12V; FRONT PAGE APPLICATION
= 140mA
IN
LOAD
IN
LOAD
3681 G25
3681 G26
1µs/DIV
0
0.1
0.2 0.3 0.4 0.5 0.6 0.7
FORWARD VOLTAGE (V)
1µs/DIV
3681 G29
3681f
6
Linear [ Linear ]
