Datasheet
1
LTC1174
LTC1174-3.3/LTC1174-5
1174fe
High Efficiency
Step-Down and Inverting
DC/DC Converter
High Efficiency Step-Down Converter
LTC1174-5 Efficiency
■
High Efficiency: Up to 94%
■
Peak Inductor Current Independent of
Inductor Value
■
Short-Circuit Protection
■
Optimized for 5V to – 5V Applications
■
Wide V
IN
Range: 4V to 18.5V
■
Low Dropout Operation
■
Low-Battery Detector
■
Pin Selectable Current Limit
■
Internal 0.9Ω Power Switch: V
IN
= 9V
■
Only Four External Components Required
■
130µA Standby Current
■
Active Low Micropower Shutdown
■
Distributed Power Systems
■
Step-Down Converters
■
Inverting Converters
■
Memory Backup Supply
■
Portable Instruments
■
Battery-Powered Equipment
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.
Under a no load condition the LTC1174 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.
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.
For applications requiring higher output current or ultra-
high efficiency, see the LTC1148 data sheet.
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
V
IN
9V
3
LTC1174-5
LB
IN
LB
OUT
I
PGM
GND
V
IN
SHUTDOWN
V
OUT
SW
2
7
6
8
1
5
4
100µH
†
100µF**
10V
5V
175mA
15µF*
25V
×3
1N5818
1174 TA01
*
**
†
(3) AVX TPSD156K025
AVX TPSD107K010
COILTRONICS CTX100-4
+
+
LOAD CURRENT (mA)
1
EFFICIENCY (%)
100
95
90
85
80
75
70
10 100
1174 TA02
200
V
IN
= 6V
V
IN
= 9V
L = 100µH
V
OUT
= 5V
I
PGM
= 0V
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.