LTC1174
LTC1174-3.3/LTC1174-5
High Efficiency
Step-Down and Inverting
DC/DC Converter
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DESCRIPTIO
EATURE
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F
The LTC®1174 is a simple current mode DC/DC converter
ideally suited for 9V to 5V, 5V to 3.3V, or 5V to –5V
operation. With an internal 0.9Ω switch (at a supply
voltage of 9V), the LTC1174 requires only four external
components to construct a complete high efficiency
DC/DC converter.
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High Efficiency: Up to 94%
Peak Inductor Current Independent of
Inductor Value
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Short-Circuit Protection
Optimized for 5V to –5V Applications
Wide VIN Range: 4V to 18.5V
Low Dropout Operation
Under a no load condition the LT1174 draws only 130µA.
In shutdown, it draws a mere 1µA making this converter
ideal for current sensitive applications. In dropout, the
internal P-channel MOSFET switch is turned on continu-
ously allowing the user to maximize the life of the battery
source.
Low-Battery Detector
Pin Selectable Current Limit
Internal 0.9Ω Power Switch: VIN = 9V
Only Four External Components Required
130µA Standby Current
Active Low Micropower Shutdown
The maximum inductor current of the LTC1174 family is
pin selectable to either 340mA or 600mA, optimizing
efficiency for a wide range of applications. Operation up to
200kHz permits the use of small surface mount inductors
and capacitors.
O U
PPLICATI
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Distributed Power Systems
Step-Down Converters
Inverting Converters
Memory Backup Supply
Portable Instruments
Battery-Powered Equipment
For applications requiring higher output current or ultra-
high efficiency, see the LTC1148 data sheet.
and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.
U
O
TYPICAL APPLICATI
High Efficiency Step-Down Converter
LTC1174-5 Efficiency
V
IN
9V
100
3 ×
15µF*
25V
+
6
V
95
IN
3
2
8
1
5
V
IN
= 6V
LB
LB
SHUTDOWN
IN
90
85
80
75
70
V
OUT
OUT
SW
V
= 9V
IN
5V
175mA
7
I
PGM
100µH†
LTC1174-5
+
100µF**
10V
1N5818
GND
4
1174 TA01
L = 100µH
V
PGM
= 5V
= 0V
OUT
(3) AVX TPSD156K025
AVX TPSD107K010
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**
I
† COILTRONICS CTX100-4
1
10
LOAD CURRENT (mA)
100 200
1174 TA02
1