LT1316 Micropower DC/DC Converter with Programmable Peak Current Limit UFEATURESDESCRIPTION ■ Precise Control of Peak Switch Current The LT®1316 is a micropower step-up DC/DC converter ■ Quiescent Current: that operates from an input voltage as low as 1.5V. A 33 µ A in Active Mode programmable input current limiting function allows pre- 3 µ A in Shutdown Mode cise control of peak switch current. Peak switch current ■ Low-Battery Detector Active in Shutdown can be set to any value between 30mA and 500mA by ■ Low Switch VCESAT: 300mV at 500mA adjusting one resistor. This is particularly useful for ■ 8-Lead MSOP and SO Packages DC/DC converters operating from high source impedance ■ Operates with VIN as Low as 1.5V inputs such as lithium coin cells or telephone lines. ■ Logic Level Shutdown Pin The fixed off-time, variable on-time regulation scheme results in quiescent current of only 33µA in active mode. U Quiescent current decreases to 3µA in shutdown with the APPLICATIONS low-battery detector still active. ■ Battery Backup ■ The LT1316 is available in 8-lead MSOP and SO packages. LCD Bias ■ Low Power – 48V to 5V/3.3V Converters , LTC and LT are registered trademarks of Linear Technology Corporation. UTYPICAL APPLICATION2-Cell to 5V Step-Up ConverterEfficiency vs Load Current L1 47µH D1 5V 90 50mA 3.3V R1 IN 6 5 1M VIN SW 1% 2.5V 7 8 IN SHDN FB + + 80 1.8VIN C2 C1 LT1316 2 CELLS 47 47 µF µF 2 1 NC LBI LBO NC RSET GND R2 324k EFFICIENCY (%) 3 4 70 1% R5 10k 1% D1: MOTOROLA MBR0520L 60 1316 TA01 L1: SUMIDA CD43-470 0.1 1 10 100 LOAD CURRENT (mA) 1316 TA02 1