LT1949-1EMS8 Ver la hoja de datos (PDF) - Linear Technology
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LT1949-1EMS8 Datasheet PDF : 8 Pages
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LT1949-1
ABSOLUTE AXI U RATI GS
(Note 1)
VIN, LBO Voltage ..................................................... 12V
SW Voltage ............................................... – 0.4V to 30V
FB Voltage .................................................... VIN + 0.3V
VC Voltage ................................................................ 2V
LBI Voltage ............................................ 0V ≤ VLBI ≤ 1V
SHDN Voltage ........................................................... 6V
Junction Temperature .......................................... 125°C
Operating Temperature Range (Note 2) ...–40°C to 85°C
Storage Temperature ........................... – 65°C to 150°C
Lead Temperature (Soldering, 10sec).................. 300°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
VC 1
FB 2
SHDN 3
GND 4
8 LBO
7 LBI
6 VIN
5 SW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 120°C/W
ORDER PART
NUMBER
LT1949-1EMS8
MS8 PART MARKING
LTQX
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 2V, VSHDN = 2V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
IQ
Quiescent Current
VFB
Feedback Voltage
VSHDN = 0V
q
8
14
mA
q
50
80
µA
1.22
1.24
1.26
V
q 1.20
1.24
1.26
V
IB
FB Pin Bias Current (Note 3)
Input Voltage Range
q
24
150
nA
q 1.7
12
V
gm
Error Amp Transconductance
AV
Error Amp Voltage Gain
Maximum Duty Cycle
∆I = 5µA
q 140
280
480 µmhos
700
V/V
q 80
85
%
Switch Current Limit (Note 4)
fOSC
Switching Frequency
Shutdown Pin Current
LBI Threshold Voltage
VIN = 2.5V, Duty Cycle = 30%
VSHDN = VIN
VSHDN = 0V
1
1.1
1.5
A
q 0.85
1.1
1.35
MHz
q
0.015
0.1
µA
q
–5
– 14
µA
190
200
210
mV
q 180
200
220
mV
LBO Output Low
LBO Leakage Current
LBI Input Bias Current (Note 5)
Low-Battery Detector Gain
ISINK = 10µA
q
VLBI = 250mV, VLBO = 5V
q
VLBI = 150mV
q
1MΩ Pull-Up
0.15
0.25
V
20
100
nA
30
120
nA
2000
V/V
Switch Leakage Current
Switch VCESAT
Reference Line Regulation
SHDN Input Voltage High
VSW = 5V
ISW = 800mA
ISW = 500mA
1.8V ≤ VIN ≤ 12V
q
q
q 1.4
0.01
3
µA
410
mV
270
400
mV
0.08
%/V
6
V
SHDN Input Voltage Low
q
0.4
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1949-1E 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.
2
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