LQH3C220 Datasheet | Linear Technology

LT1945 Dual Micropower DC/DC Converter with Positive and Negative Outputs Features s s DESCRIPTIO s s s s s U APPLICATIO S s s s s Generates Well-Regulated Positive and Negative Outputs Low Quiescent Current: 20µA in Active Mode (per Converter) <1µA in Shutdown Mode Operates with VIN as Low as 1.2V Low VCESAT Switch: 250m V at 300m A Uses Small Surface Mount ponents High Output Voltage: Up to ±34V Tiny 10-Pin MSOP Package Small TFT LCD Panels Handheld puters Battery Backup Digital Cameras The LT®1945 is a dual micropower DC/DC converter in a 10-pin MSOP package. Each converter is designed with a 350m A current limit and an input voltage range of 1.2V to 15V, making the LT1945 ideal for a wide variety of applications. Both converters feature a quiescent current of only 20µA at no load, which further reduces to 0.5µA in shutdown. A current limited, fixed off-time control scheme conserves operating current, resulting in high efficiency over a broad range of load current. The 36V switch allows high voltage outputs up to ±34V to be easily generated without the use of costly transformers. The LT1945’s low off-time of 400ns permits the use of tiny, low profile inductors and capacitors to minimize footprint and cost in space-conscious portable applications. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO VIN 2.7V TO 5V L1 10µH 8 VIN 2 C1 4.7µF SHDN1 LT1945 4 SHDN2 3 7 9 FB2 6 Dual Output (+12V, - 20V) Converter C4 0.1µF 10 SW1 NFB1 1 D2 5 24.9k C2 1µF 100p F 365k 85 +12V OUTPUT 80 EFFICIENCY (%) D1 - 20V 10m A 75 70 65 60 GND PGND PGND SW2 115k C3 1µF 12V 20m A 1945 TA01 55 50 0.1 1 10 LOAD CURRENT (m A) 100 1945 TA01a 4.7p F L2 10µH C1: TAIYO YUDEN JMK212BJ475 C2, C3: TAIYO YUDEN TMK316BJ105 C4: TAIYO YUDEN EMK107BJ104 D1, D2, D3: ZETEX ZHCS400 L1, L2: MURATA LQH3C100 D3 1M Efficiency at VIN = 3.6V - 20V OUTPUT 1945f LT1945 ABSOLUTE...