LT1940/LT1940L
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Maximum Load Current,
OUT = 1.8V
Maximum Load Current,
VOUT = 3.3V
V
Switch VCESAT
400
300
200
100
0
1.8
1.6
1.4
1.2
1.0
1.8
1.6
1.4
1.2
1.0
T
= 25°C
SLOPE COMPENSATION REQUIRES
A
L > 2.2µH FOR V < 7 WITH V
= 3.3V
IN
OUT
L = 4.7µH
L = 2.2µH
L = 3.3µH
L = 1.5µH
L = 2.2µH
L = 1µH
1.0
1.5
0
2.0
0.5
2
4
6
8
10 12 14 16
INPUT VOLTAGE (V)*
0
5
10
15
20
25
0
SW CURRENT (A)
INPUT VOLTAGE (V)*
1940 G06
1940 G04
1940 G05
VOUT vs Temperature
Current Limit vs Duty Cycle
Boost Pin Current
40
30
20
10
0
3.40
3.35
3.30
3.25
3.20
3.0
2.5
2.0
1.5
1.0
0.5
0
CHANNEL 1, FIGURE 1, V = 12V
IN
TYPICAL
MINIMUM
–50
0
25
50
75 100 125
–25
1.0
1.5
0
20
40
60
80
100
0
2.0
0.5
DUTY CYCLE (%)
TEMPERATURE (°C)
SWITCH CURRENT (A)
1940 G08
1940 G09
1940 G07
Frequency vs Temperature
IRUN/SS vs Temperature
Frequency Foldback
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
3.0
2.5
2.0
1.5
1.0
0.5
0
1.3
1.2
1.1
1.0
0.9
–50 –25
0
25
50
75
100 125
–50
0
25
50
75 100 125
0
0.4
0.6
0.8
1.0
1.2
–25
0.2
TEMPERATURE (°C)
FEEDBACK VOLTAGE (V)
TEMPERATURE (°C)
1940 G11
1940 G10
1940 G12
*Maximum VIN is 7V for LT1940L.
1940fa
4
Linear [ Linear ]
