lt1940l Linear Technology Corporation, lt1940l Datasheet - Page 4

• Manufacturer Part Number: lt1940l
• Description: Lt1940l - Dual Monolithic 1.4a, 1.1mhz Step-down Switching Regulator
• Manufacturer: Linear Technology Corporation

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