特性 Features

n Wide 4.5V to 40V Input Voltage Range

n 3.3V,5V,12V, and adjustable versions

n Output Adjustable from 1.23V to 37V

n Maximum Duty Cycle 100

n Minimum Drop Out 1.5V

n Fixed 150KHz Switching Frequency

n 2A Constant Output Current Capability

n Internal Optimize Power Transistor

n High efficiency

n Excellent line and load regulation

n TTL shutdown capability

n ON/OFF pin with hysteresis function

n Built in thermal shutdown function

n Built in current limit function

n Built in second current limit function

n Available in SOIC8 package

Applications

n LCD Monitor and LCD TV

n Digital Photo Frame

n Set-up Box

n ADSL Modem

n Telecom / Networking Equipment

General Description

The XL1509 is a 150 KHz fixed frequency

PWM buck (step-down) DC/DC converter,

capable of driving a 2A load with high

efficiency, low ripple and excellent line and

load regulation. Requiring a minimum

number of external components, the regulator

is simple to use and include internal

frequency compensation and a

fixed-frequency oscillator.

The PWM control circuit is able to adjust the

duty ratio linearly from 0 to 100. An enable

function, an over current protection function

is built inside. When second current limit

function happens, the operation frequency

will be reduced from 150KHz to 50KHz. An

internal compensation block is built in to

minimize external component count.