LTC1174 LTC1174-3.3/LTC1174-5 High Efficiency Step-Down and Inverting DC/DC Converter UFEATURESDESCRIPTIO ■ High Efficiency: Up to 94% The LTC®1174 is a simple current mode DC/DC converter ■ Peak Inductor Current Independent of ideally suited for 9V to 5V, 5V to 3.3V or 5V to – 5V Inductor Value operation. With an internal 0.9Ω switch (at a supply ■ Short-Circuit Protection voltage of 9V), the LTC1174 requires only four external ■ Optimized for 5V to – 5V Applications components to construct a complete high efficiency ■ Wide VIN Range: 4V to 18.5V DC/DC converter. ■ Low Dropout Operation Under a no load condition the LTC1174 draws only 130µA. ■ Low-Battery Detector In shutdown, it draws a mere 1µA making this converter ■ Pin Selectable Current Limit ideal for current sensitive applications. In dropout, the ■ Internal 0.9Ω Power Switch: VIN = 9V internal P-channel MOSFET switch is turned on continu- ■ Only Four External Components Required ously allowing the user to maximize the life of the battery ■ 130µA Standby Current source. ■ Active Low Micropower Shutdown The maximum inductor current of the LTC1174 family is U pin selectable to either 340mA or 600mA, optimizing APPLICATIO S efficiency for a wide range of applications. Operation up to ■ Distributed Power Systems 200kHz permits the use of small surface mount inductors ■ Step-Down Converters and capacitors. ■ Inverting Converters For applications requiring higher output current or ultra- ■ Memory Backup Supply high efficiency, see the LTC1148 data sheet. ■ Portable Instruments ■ Battery-Powered Equipment , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. UTYPICAL APPLICATIOHigh Efficiency Step-Down ConverterLTC1174-5 Efficiency 100 VIN 9V 6 + 15µF* 95 25V VIN = 6V VIN ×3 3 8 LB 90 IN SHUTDOWN V 2 1 IN = 9V LBOUT VOUT 7 5 5V 85 IPGM SW 100µH† 175mA LTC1174-5 + EFFICIENCY (%) 80 100µF** GND 1N5818 10V L = 100µH 4 75 VOUT = 5V 1174 TA01 IPGM = 0V * (3) AVX TPSD156K025 70 ** AVX TPSD107K010 1 10 100 200 † COILTRONICS CTX100-4 LOAD CURRENT (mA) 1174 TA02 1174fe 1