Datasheet

LT3970 Series
5
3970fc
No-Load Supply Current
No-Load Supply Current Maximum Load Current
Maximum Load Current Maximum Load Current Load Regulation
Typical perFormance characTerisTics
Switch Current Limit
Switch Current Limit Switching Frequency
T
A
= 25°C, unless otherwise noted.
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
1.5
2.0
2.5
3.0
10 20
30
40
3970 G07
3.5
4.0
5 15
25
35
FRONT PAGE APPLICATION
V
OUT
= 3.3V
R1 = 1MΩ
R2 = 576k
LT3970-5
LT3970-3.3
TEMPERATURE (°C)
–50
SUPPLY CURRENT (µA)
9
12
15
25 75 150
3970 G08
6
3
0
–25 0
50
100 125
FRONT PAGE APPLICATION
V
IN
= 12V
V
OUT
= 3.3V
R1 = 1M
R2 = 576k
INPUT VOLTAGE (V)
5
350
LOAD CURRENT (mA)
400
450
500
550
10 15 20 25
3870 G09
30 35 40
FRONT PAGE APPLICATION
V
OUT
= 3.3V
TYPICAL
MINIMUM
INPUT VOLTAGE (V)
5
350
LOAD CURRENT (mA)
400
450
500
600
550
10 15 20 25
3870 G10
30 35 40
FRONT PAGE APPLICATION
V
OUT
= 5V
TYPICAL
MINIMUM
TEMPERATURE (°C)
–50
LOAD CURRENT (mA)
300
400
500
600
25 75
3970 G11
200
100
0
–25 0
50
100 150125
LIMITED BY MAXIMUM
JUNCTION TEMPERATURE;
θ
JA
= 76°C/W
FRONT PAGE APPLICATION
V
IN
= 12V
V
OUT
= 5V
LIMITED BY CURRENT LIMIT H GRADE
LOAD CURRENT (mA)
0
LOAD REGULATION (%)
0.15
150
3970 G12
0
–0.10
50 100 200
–0.15
–0.20
0.20
0.10
0.05
–0.05
250 300 350
FRONT PAGE APPLICATION
REFERENCED FROM V
OUT
AT 100mA LOAD
DUTY CYCLE (%)
0
200
SWITCH CURRENT LIMIT (mA)
300
400
500
600
700
800
20 40 60 80
3970 G13
100
SWITCH PEAK
CURRENT LIMIT
CATCH DIODE VALLEY CURRENT LIMIT
TEMPERATURE (°C)
–50
200
SWITCH CURRENT LIMIT (mA)
300
400
500
600
0 50
100
150
3970 G14
700
800
–25 25
75
125
SWITCH PEAK CURRENT LIMIT
CATCH DIODE VALLEY CURRENT LIMIT
TEMPERATURE (°C)
–50
0
FREQUENCY (MHz)
0.4
0.8
1.2
1.6
2.4
–25
0 25 50 75
3970 G15
100 125 150
2.0
0.2
0.6
1.0
1.4
2.2
1.8