LT1945 Datasheet | Linear Technology

Features n Generates Well-Regulated Positive and Negative Outputs n Low Quiescent Current: 20μA in Active Mode (per Converter) <1μA in Shutdown Mode n Operates with VIN as Low as 1.2V n Low VCESAT Switch: 250m V at 300m A n Uses Small Surface Mount ponents n High Output Voltage: Up to ±34V n Tiny 10-Pin MSOP Package APPLICATIONS n Small TFT LCD Panels n Handheld puters n Battery Backup n Digital Cameras Dual Micropower DC/DC Converter with Positive and Negative Outputs DESCRIPTION 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. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Dual Output (+12V, - 20V) Converter VIN 2.7V TO 5V C1 4.7μF L1 10μH C4 0.1μF D1 8 10 VIN 2 SHDN1 SW1 1 NFB1 4 SHDN2 5 FB2 GND PGND PGND SW2 37 96 D2 100p F 365k 24.9k - 20V 10m A C2 1μF L2 10μH C1: TAIYO YUDEN JMK212BJ475 C2, C3: TAIYO YUDEN TMK316BJ105 C4: TAIYO YUDEN EMK107BJ104 D1, D2, D3: ZETEX ZHCS400 L1, L2: MURATA LQH3C100 4.7p F...