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