XLSEMI

XL1509

2A 150KHz 40V Buck DC to DC Converter 

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.