lt1940l Linear Technology Corporation, lt1940l Datasheet - Page 3

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

temperature range, otherwise specifications are at T
PARAMETER
Foldback Frequency
Switch Current Limit
Switch V
Switch Leakage Current
Minimum Boost Voltage Above Switch (Note 4)
BOOST Pin Current
RUN/SS Current
RUN/SS Threshold
PG Threshold Offset
PG Voltage Output Low
PG Pin Leakage
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1940E is guaranteed to meet performance specifications
from 0 C to 70 C. Specifications over the –40 C to 85 C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
ELECTRICAL CHARACTERISTICS
TYPICAL PERFOR A CE CHARACTERISTICS
90
80
70
60
50
Efficiency, V
0
V
L = 2.2 H (SUMIDA CR43-2R2)
T
CESAT
OUT
A
= 25 C
= 1.8V
LOAD CURRENT (A)
0.5
OUT
V
IN
= 1.8V
= 5V
1.0
W
1940 G01
U
1.5
100
90
80
70
60
50
Efficiency, V
A
0
V
L = 3.3 H (SUMIDA CR43-3R3)
T
= 25 C. V
A
OUT
CONDITIONS
V
Note 3
I
I
I
V
V
V
= 25 C
V
SW
SW
SW
FB
FB
FB
PG
IN
= 3.3V
= 18V
The
= 1V, I
= 0V
= 1A
= 1A
= 1A
Rising
= 2V
LOAD CURRENT (A)
0.5
IN
PG
OUT
denotes the specifications which apply over the full operating
= 5V, V
V
= 250 A
IN
= 3.3V
Note 3: Current limit is guaranteed by design and/or correlation to static
test. Slope compensation reduces current limit at high duty cycle.
Note 4: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
= 12V
BOOST
1.0
V
= 8V unless otherwise noted. (Note 2)
IN
= 5V
1940 G02
1.5
100
90
80
70
60
LT1940/LT1940L
Efficiency, V
0
V
L = 4.7 H (SUMIDA CR43-4R7)
T
OUT
A
MIN
1.8
0.3
= 25 C
90
V
IN
= 5V
= 18V
LOAD CURRENT (A)
0.5
0.22
TYP
150
210
125
OUT
2.4
1.8
2.3
0.6
0.1
20
V
IN
= 5V
= 12V
MAX
320
160
3.2
2.5
0.4
1.0
10
30
1
V
IN
UNITS
= 8V
1940 G03
1940fa
3
kHz
mV
mA
mV
1.5
A
A
V
A
V
V
A