LT3681
TYPICAL PERFOR A CE CHARACTERISTICS
T
A
= 25°C unless otherwise noted.
Efficiency (V
OUT
= 5.0V)
100
90
80
70
EFFICIENCY (%)
60
50
40
30
20
10
0
0.0001
0.001
L: NEC PLC-0745-4R7
f: 800kHz
0.01
0.1
LOAD CURRENT (A)
1
10
3681 G01
V
IN
= 12V
V
IN
= 24V
EFFICIENCY (%)
60
50
40
30
20
10
0
0.0001
0.001
V
IN
= 24V
V
IN
= 12V
EFFICIENCY (%)
No Load Supply Current
90
80
90
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
70
60
50
40
30
20
10
0
0
FRONT PAGE APPLICATION
5
10
20
25
15
INPUT VOLTAGE (V)
30
35
3681 G04
LOAD CURRENT (A)
Maximum Load Current
4.0
3.5
LOAD CURRENT (A)
3.0
2.5
2.0
1.5
1.0
5
10
20
25
15
INPUT VOLTAGE (V)
30
3681 G07
SWITCH CURRENT LIMIT(A)
SWITCH CURRENT LIMIT (A)
V
OUT
= 5.0V
L = 4.7µH
f = 800 kHz
4
U W
Efficiency (V
OUT
= 3.3V)
100
90
80
70
V
IN
= 7V
90
85
80
Efficiency vs Switching Frequency
V
IN
= 12V
V
IN
= 24V
75
70
65
60
L: NEC PLC-0745-4R7
f: 800kHz
0.01
0.1
LOAD CURRENT (A)
1
10
3681 G02
55
50
0
0.5
V
OUT
= 3.3V
L = 10µH
LOAD = 1A
1
2
2.5
1.5
SWITCHING FREQUENCY (MHz)
3
3681 G03
No Load Supply Current vs
Temperature
100
V
IN
= 12V
V
OUT
= 3.3V
4.0
3.5
INCREASED SUPPLY
CURRENT DUE TO CATCH
DIODE LEAKAGE AT
HIGH TEMPERATURE
3.0
2.5
2.0
1.5
1.0
–20
60
0
20
40
TEMPERATURE (°C)
80
3681 G05
Maximum Load Current
80
70
60
50
40
–40
V
OUT
= 3.3V
L = 4.7µH
f = 800 kHz
5
10
25
20
15
INPUT VOLTAGE (V)
30
3681 G06
Switch Current Limit
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0
20
60
40
DUTY CYCLE (%)
80
100
3681 G08
Switch Current Limit
4.5
4.0
3.0
2.5
2.0
1.5
1.0
0.5
0
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
DUTY CYCLE = 90 %
DUTY CYCLE = 10 %
3681 G09
3681f
LINER [ LINEAR TECHNOLOGY ]
