描述 Description

The SC1417B is a fixed frequency, current mode step-up dc-dc converter. It operates over a wide input supply range of 1.5V to 12V, making it suitable for battery input and TFT-LCD applications. The 620kHz constant frequency oscillator minimizes the size of external components and allows simple filtering for noise sensitive environments. The integrated power NPN supports peak currents of up to 0.9A enabling the device to support 150mA at 15V from a 5V supply. The maximum switch duty cycle of 85 (typical) allows output to input voltage ratios as high as 6.5 in step-up configurations, thus allowing 2V to 12V boost operation.

The SC1417B features a low battery detector and a 200mV reference circuit which remains active during shut down. The part consumes less than 50μA in shutdown. The low battery detect output goes low when the input battery voltage has dropped below a user programmable level. Pulse-by-pulse current limit and thermal shutdown protect the converter during load faults.

The SC1417B is available in a MSOP-8 surface mount package.

特性 Features

? Operates from 1.5V to 12V supply voltage

? High efficiency >85

? 150mA @ 15V from 5V input

? Internal switch peak current of 0.9A

? Programmable output voltage

? Powers up into full load

? Pulse-by-pulse current limit/thermal shutdown

? 620kHz fixed frequency current mode converter

? Low current shutdown mode extends battery life

? 18V output capability

? Low battery detector

? MSOP-8 package. Available in Lead-free package, fully WEEE and RoHS compliant

? Pin-for-pin compatible with LT1317B

Applications

? TFT-LCD Bias supplies

? Constant current LED bias supplies

? Pagers

? GPS receivers

? Battery backup

? SEPIC converters