LTC1174_15 Datasheet, PDF (1/20 Pages) Linear Technology – High Efficiency Step-Down and Inverting DC/DC Converter

FEATURES
■ _{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}
■ _{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}
U
APPLICATIO S
■ _{Distributed Power Systems}
■ _{Step-Down Converters}
■ _{Inverting Converters}
■ _{Memory Backup Supply}
■ _{Portable Instruments}
■ _{Battery-Powered Equipment}
LTC1174
LTC1174-3.3/LTC1174-5
High Efficiency
Step-Down and Inverting
DC/DC Converter
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.
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.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
High Efficiency Step-Down Converter
V_IN
9V
6
3
LB_IN
2
LB_OUT
7 _IPGM
V_IN
8
SHUTDOWN
V_OUT ¹
SW ⁵
LTC1174-5
GND
4
* (3) AVX TPSD156K025
** AVX TPSD107K010
† _{COILTRONICS CTX100-4}
+ 15µF*
25V
×3
100µH^†
+
1N5818
5V
175mA
100µF**
10V
1174 TA01
100
95
90
85
80
75
70
1
LTC1174-5 Efficiency
V_IN = 6V
V_IN = 9V
L = 100µH
V_OUT = 5V
I_PGM = 0V
10
LOAD CURRENT (mA)
100 200
1174 TA02
1174fe
1