datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 1 features ? wide 4.5v to 40v input voltage range ? output adjustable from 1.235v to 37v ? minimum drop out 1.5v ? fixed 150khz switching frequency ? 2a constant output current capability ? internal optimize power transistor ? excellent line and load regulation ? ttl shutdown capability ? on/off pin with hysteresis function ? with output constant current loop ? built in thermal shutdown function ? built in current limit function ? built in output over voltage protection ? sop8-ep (exposed pad) package applications ? car charger ? battery charger ? led constant current driver general description the xl4001 is a 150khz 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. an internal compensation block is built in to minimize external component count. figure1. package type of xl4001
datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 2 pin configurations xl4001 $ 4 4 8 ( / % 4 8 ' # & / 7 * / 7 * / figure2. pin configuration of xl4001 (top view) table 1 pin description pin number pin name description 1,2 sw power switch output pin (sw). ou tput is the switch node that supplies power to the output. 3 gnd ground pin.(note: connected the back exposed pad to pin3 .) 4 fb feedback pin (fb). through an external resistor divider network, feedback senses the out put voltage and regulates it. the feedback threshold voltage is 1.235v. 5 cs output current sens e pin; (iload=0.155v/rcs) 6 en enable pin. drive en pin low to turn on the device, drive it high to turn it off. floating is default low. 7,8 vin supply voltage input pin. xl4001 operates from a 4.5v to 40v dc voltage. bypass vin to gnd with a suitably la rge capacitor to eliminate noise on the input.
datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 3 function block figure3. function block diagram of xl4001 typical application circuit (car charger) figure4. xl4001 typical applicatio n circuit (li battery charger)
datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 4 typical application circuit (buc k led constant current driver) xl4001 $ * / v g 7 $ $ 0 6 5 v g 7 % / - v i 7 _ 7
( / % 7 * / ' # 4 8 $ 4 3 d t & / - & % 8 _ 8 3 , 3 7 0 6 5 figure5. xl4001 typical application circ uit (led constant current driver) ordering information order information marking id package type packing type supplied as XL4001E1 XL4001E1 sop8-ep 2500 units on tape & reel xlsemi pb-free products, as designated with ?e1? suffix in the par number, are rohs compliant. absolute maximum ratings
note1 parameter symbol value unit input voltage vin -0.3 to 45 v fb pin voltage v fb -0.3 to vin v en pin voltage ven -0.3 to vin v sw pin voltage v sw -0.3 to vin v power dissipation p d internally limited mw thermal resistance (junction to ambient, no heatsink, free air) r ja 60 oc/w operating junction temperature t j -40 to 125 oc storage temperature t stg -65 to 150 oc lead temperature (soldering, 10 sec) t lead 260 oc esd (hbm) 2000 v note1: stresses greater than those listed under maximum ratings may cause permanent damage to the device. this is a stress rating only and functional operation of the device at these or any other conditions above those in dicated in the operation is not implied. exposure to absolute maximum rating conditions for extended periods may affect reliability.
datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 5 xl4001 electrical characteristics t a = 25 ;unless otherwise specified. symbol parameter test condition min. typ. max. unit system parameters test circuit figure4 vfb feedback voltage vin = 8v to 32v, vout=5v iload=0.2a to 2a 1.21 1.235 1.26 v efficiency ? vin=12v ,vout=5v iout=2a - 83 - % electrical characteristics (dc parameters) vin = 12v, gnd=0v, vin & gnd parallel connect a 220uf/50v capacitor; iout=500ma, t a = 25 ; the others floating unless otherwise specified. parameters symbol test condition min. typ. max. unit input operation voltage vin 4.5 40 v shutdown supply current i stby v en =5v 80 200 ua quiescent supply current i q v en =0v, v fb =vin 2 5 ma oscillator frequency fosc 127 150 172 khz switch current limit i l v fb =0 3 a en pin threshold v en high (regulator off) low (regulator on) 1.4 0.8 v output saturation voltage v ce v fb =0v i sw =2a 1.1 1.4 v constant current sense voltage v cs 0.140 0.155 0.170 v
datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 6 schottky diode selection table current surface mount through hole vr (the same as system maximum input voltage) 20v 30v 40v 50v 60v 1a ? 1n5817 1n5818 1n5819 ? 1n5820 1n5821 1n5822 ? mbr320 mbr330 mbr340 mbr350 mbr360 ? sk32 sk33 sk34 sk35 sk36 ? 30wq03 30wq04 30wq05 ? 31dq03 31dq04 31dq05 3a ? sr302 sr303 sr304 sr305 sr306
datasheet 2a 150khz 40v buck dc/dc converter with constant current loop xl4001 rev 1.2 www.xlsemi.com 7 package information (sop8-ep)
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