LTC1174
LTC1174-3.3/LTC1174-5
High Efficiency
Step-Down and Inverting
DC/DC Converter
U
FEATURES
DESCRIPTIO
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.
■
High Efficiency: Up to 94%
■
Peak Inductor Current Independent of
Inductor Value
Short-Circuit Protection
■
■
Optimized for 5V to –5V Applications
■
Wide VIN Range: 4V to 18.5V
■
Low Dropout Operation
UnderanoloadconditiontheLTC1174drawsonly130µA.
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.
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APPLICATIO S
■
Distributed Power Systems
■
Step-Down Converters
■
Inverting Converters
For applications requiring higher output current or ultra-
high efficiency, see the LTC1148 data sheet.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
■
Memory Backup Supply
■
Portable Instruments
■
Battery-Powered Equipment
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TYPICAL APPLICATIO
High Efficiency Step-Down Converter
LTC1174-5 Efficiency
100
V
IN
9V
95
15µF*
25V
+
6
V
= 6V
IN
V
IN
×3
3
2
8
1
5
90
85
80
75
70
LB
LB
SHUTDOWN
IN
V
= 9V
IN
V
OUT
OUT
SW
5V
175mA
7
I
PGM
100µH†
LTC1174-5
+
100µF**
10V
1N5818
GND
4
L = 100µH
V
= 5V
= 0V
OUT
PGM
1174 TA01
I
(3) AVX TPSD156K025
AVX TPSD107K010
*
**
1
10
LOAD CURRENT (mA)
100 200
† COILTRONICS CTX100-4
1174 TA02
1174fe
1