Datasheet LT1617, LT1617-1 (Analog Devices)

LT1617/LT1617-1 Micropower Inverting DC/DC Converters in SOT-23
U FEATURES DESCRIPTIO
■
Low Quiescent Current:
The LT®1617/LT1617-1 are micropower inverting DC/DC
20
µ
A in Active Mode
converters in a 5-lead SOT-23 package. The LT1617 is
<1
µ
A in Shutdown Mode
designed for higher power systems with a 350mA current ■
Operates with V
limit and an input voltage range of 1.2V to 15V, whereas
IN as Low as 1V
■ Low V the LT1617-1 is intended for lower power and single-cell CESAT Switch: 250mV at 300mA ■ Uses Small Surface Mount Components applications with a 100mA current limit and an extended ■ High Output Voltage: Up to – 34V input voltage range of 1V to 15V. Otherwise, the two ■ Tiny 5-Lead SOT-23 Package devices are functionally equivalent. Both devices feature a quiescent current of only 20µA at no load, which further
U
reduces to 0.5µA in shutdown. A current limited, fixed off-
APPLICATIO S
time control scheme conserves operating current, result- ■ ing in high efficiency over a broad range of load current. LCD Bias The 36V switch allows high voltage outputs up to – 34V to ■ Handheld Computers ■ be easily generated without the use of costly transformers. Battery Backup ■ The LT1617’s low off-time of 400ns permits the use of Digital Cameras 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.
U TYPICAL APPLICATION 1-Cell Li-Ion to –15V Inverting Converter Efficiency
C3 80 L1 L2 0.22µF 22µH 22µH VIN –15V 75 V 2.5V TO 4.2V 12mA IN = 4.2V 5 1 VIN SW 70 D1 267k VIN = 2.5V LT1617 C2 4 3 4.7µF 65 SHDN NFB GND C1 24.9k EFFICIENCY (%) 60 4.7µF 2 55 C1: TAIYO YUDEN LMK316BJ475 1617/-1 TA01 C2: TAIYO YUDEN EMK316BJ475 C3: TAIYO YUDEN TMK316BJ224 50 0.1 1 10 30 L1, L2: MURATA LQH3C220K34 D1: MOTOROLA MBR0530 LOAD CURRENT (mA) 1617/-1 TA01a 1