LT1949 Ver la hoja de datos (PDF) - Linear Technology
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LT1949 Datasheet PDF : 8 Pages
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LT1949
ELECTRICAL CHARACTERISTICS The q denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 2V, VSHDN = 2V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
Switch VCESAT
Reference Line Regulation
SHDN Input Voltage High
ISW = 800mA
ISW = 500mA
1.8V ≤ VIN ≤ 12V
q
q
q 1.4
410
400
0.08
0.15
6
SHDN Input Voltage Low
q
0.4
UNITS
mV
mV
%/V
V
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1949E 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.
Note 3: Bias current flows into FB pin.
Note 4: Switch current limit guaranteed by design and/or correlation to
static tests. Duty cycle affects current limit due to ramp generator.
Note 5: Bias current flows out of LBI pin.
TYPICAL PERFOR A CE CHARACTERISTICS
Oscillator Frequency
700
650
–40°C
25°C
600
85°C
550
500
02
4
6 8 10 12
INPUT VOLTAGE
1949 G01
Switch Voltage Drop (VCESAT)
1.0
0.8
0.6
85°C
25°C
0.4
–40°C
0.2
0
0 0.2 0.4 0.6 0.8 1.0 1.2
SWITCH CURRENT (A)
1949 G04
Switch Current Limit
1.3
1.2
1.1
1.0
0.9
0.8
0
20
40
60
80 100
DUTY CYCLE (%)
1949 G02
Feedback Voltage
1.25
1.24
1.23
1.22
1.21
1.20
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
1949 G05
Switch Current Limit,
Duty Cycle = 30%
1.3
1.2
1.1
1.0
0.9
0.8
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
1949 G03
Quiescent Current, SHDN = 2V
4.6
4.5
4.4
4.3
4.2
4.1
4.0
3.9
3.8
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
1949 G06
3
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