1
LT1373
250kHz Low Supply Current
High Efficiency
1.5A Switching Regulator
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Boost Regulators
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CCFL Backlight Driver
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Laptop Computer Supplies
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Multiple Output Flyback Supplies
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Inverting Supplies
The LT
®
1373 is a low supply current high frequency
current mode switching regulator. It can be operated in all
standard switching configurations including boost, buck,
flyback, forward, inverting and “Cuk.” A 1.5A high effi-
ciency switch is included on the die, along with all oscilla-
tor, control and protection circuitry. All functions of the
LT1373 are integrated into 8-pin SO/PDIP packages.
Compared to the 500kHz LT1372, which draws 4mA of
quiescent current, the LT1373 switches at 250kHz, typi-
cally consumes only 1mA and has higher efficiency. High
frequency switching allows for small inductors to be used.
All surface mount components consume less than 0.6
square inch of board space.
New design techniques increase flexibility and maintain
ease of use. Switching is easily synchronized to an exter-
nal logic level source. A logic low on the shutdown pin
reduces supply current to 12µA. Unique error amplifier
circuitry can regulate positive or negative output voltage
while maintaining simple frequency compensation tech-
niques. Nonlinear error amplifier transconductance re-
duces output overshoot on start-up or overload recovery.
Oscillator frequency shifting protects external compo-
nents during overload conditions.
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1mA I
Q
at 250kHz
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Uses Small Inductors: 15µH
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All Surface Mount Components
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Only 0.6 Square Inch of Board Space
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Low Minimum Supply Voltage: 2.7V
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Constant Frequency Current Mode
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Current Limited Power Switch: 1.5A
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Regulates Positive or Negative Outputs
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Shutdown Supply Current: 12µA Typ
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Easy External Synchronization
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8-Pin SO or PDIP Packages
, LTC and LT are registered trademarks of Linear Technology Corporation.
OUTPUT CURRENT (mA)
1
70
EFFICIENCY (%)
80
90
10 100 1000
LT1373 • TA02
60
50
100
V
IN
= 5V
f = 250kHz
LT1373
V
IN
V
C
5V
1
2
8
5
4
6, 7
SUMIDA CD75-220KC (22µH) OR
COILCRAFT D03316-153 (15µH)
AVX TPSD226M025R0200
GND
FB
LT1373 • TA01
V
SW
S/S
L1*
22µH
C1**
22µF
C4**
22µF
C2
0.01µF
R3
5k
R2
24.9k
1%
R1
215k
1%
*
**
V
OUT
†
12V
†
MAX I
OUT
D1
MBRS120T3
ON
OFF
L1
15µH
22µH
I
OUT
0.3A
0.35A
+
+
5V-to-12V Boost Converter
12V Output Efficiency
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U