LT1934/LT1934-1 Micropower Step-Down Switching Regulators in ThinSOT and DFN FEATURESDESCRIPTION n Wide Input Voltage Range: 3.2V to 34V The LT®1934 is a micropower step-down DC/DC converter n Micropower Operation: IQ = 12μA with internal 400mA power switch, packaged in a low n 5V at 250mA from 6.5V to 34V Input (LT1934) profi le (1mm) ThinSOT. With its wide input range of 3.2V n 5V at 60mA from 6.5V to 34V Input (LT1934-1) to 34V, the LT1934 can regulate a wide variety of power n 3.3V at 250mA from 4.5V to 34V Input (LT1934) sources, from 4-cell alkaline batteries and 5V logic rails n 3.3V at 60mA from 4.5V to 34V Input (LT1934-1) to unregulated wall transformers and lead-acid batteries. n Low Shutdown Current: <1μA Quiescent current is just 12μA and a zero current shut- n Low VCESAT Switch: 200mV at 300mA down mode disconnects the load from the input source, n Low Profi le (1mm) SOT-23 (ThinSOT™) and simplifying power management in battery-powered sys- (2mm × 3mm × 0.8mm) 6-Pin DFN Package tems. Burst Mode® operation and the low drop internal power switch result in high effi ciency over a broad range of load current. APPLICATIONS The LT1934 provides up to 300mA of output current. The n Wall Transformer Regulation LT1934-1 has a lower current limit, allowing optimum n Automotive Battery Regulation choice of external components when the required output n Standby Power for Portable Products current is less than 60mA. Fast current limiting protects n Distributed Supply Regulation the LT1934 and external components against shorted n Industrial Control Supplies outputs, even at 34V input. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION3.3V Step-Down ConverterEffi ciency D2 100 LT1934 VIN = 12V 90 0.22μF BOOST L1 47μH V VOUT = 5V OUT VIN VIN SW 3.3V 4.5V TO 34V 80 C2 250mA D1 VOUT = 3.3V 2.2μF LT1934 10pF 1M + 70 ON OFF SHDN C1 FB EFFICIENCY (%) 100μF GND 604k 60 C1: SANYO 4TPB100M 50 1934 TA01 C2: TAIYO YUDEN GMK325BJ225MN 0.1 1 10 100 D1: ON SEMICONDUCTOR MBR0540 LOAD CURRENT (mA) D2: CENTRAL CMDSH-3 1934 TA02 L1: SUMIDA CDRH4D28-470 1934fe 1