datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 1 features n wide 5v to 32v input voltage range n output adjustable from 0.8v to 30v n maximum duty cycle 100% n minimum drop out 0.6v n fixed 300khz switching frequency n 5a constant output current capability n internal optimize power mosfet n high e fficiency n excellent line and load regulation n ttl shutdown capability n en pin with hysteresis function n built in thermal shutdown function n built in current limit function n built in output short protection function n available in to-263 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 XL4005 is a 300khz fixed frequency pwm buck (step-down) dc/dc converter, capable of driving a 5a 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 short protection function happens, the operation frequency will be reduced from 300khz to 60khz. an internal compensation block is built in to minimize external component count. figure1. package type of XL4005
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 2 pin configurations figure2. pin configuration of XL4005 (top view) table 1 pin description pin number pin name description 1 gnd ground pin. care must be taken in layout. this pin should be placed outside of the schottky diode to output capacitor ground path to prevent switching current spikes from inducing voltage noise into XL4005. 2 fb feedback pin (fb). through an external resistor divider network, fb senses the output voltage and regulates it. the feedback threshold voltage is 0.8v. 3 sw power switch output pin (sw). sw is the switch node that supplies power to the output. 4 en enable pin. drive en pin high to turn on the device, drive it low to turn it off. 5 vin supply voltage input pin. XL4005 operates from a 5v to 32v dc voltage. bypass vin to gnd with a suitably large capacitor to eliminate noise on the input.
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 3 function block figure3. function block diagram of XL4005 typical application circuit XL4005 cin 470uf/50v c1 105 r1 2k r2 10.5k cff 33n cout 470uf/50v d1 1n5824 l 33uh/5a +24v load 5 3 2 vin fb sw vout 5v/5a 24v ~ 5v/5a vout=0.8*(1+r2/r1) gnd en 4 1 figure4. XL4005 typical application circuit 24v~5v/5a
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 4 ordering information order information marking id package type packing type supplied as XL4005e1 XL4005e1 to263-5l 800 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 35 v feedback pin voltage v fb -0.3 to vin v en pin voltage v en -0.3 to vin v output switch pin voltage v output -0.3 to vin v power dissipation p d internally limited mw thermal resistance (to263) (junction to ambient, no heatsink, free air) r ja 30 o c/w operating junction temperature t j -40 to 125 o c storage temperature t stg -65 to 150 o c lead temperature (soldering, 10 sec) t lead 260 o c 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 indicated in the operation is not implied. exposure to absolute maximum rating conditions for extended periods may affect reliability.
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 5 XL4005 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 = 5v to 32v, vout=5v iload=0.5a to 5a 0.776 0.8 0.824 v efficiency ? vin=12v ,vout=5v iout=5a - 90 - % 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 5 32 v shutdown supply current i stby v en =0v 60 200 ua quiescent supply current i q v en =2v, v fb =vin 3 5 ma oscillator frequency fosc 240 300 360 khz switch current limit i l v fb =0 8 a en pin threshold v en high (regulator on) low (regulator off) 1.4 0.8 v i h v en =2v (on) 1 15 ua en pin input leakage current i l v en =0v (off) 1 15 ua max. duty cycle d max v fb =0v 100 %
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 6 test circuit and layout guidelines figure5. standard test circuits and layout guides select r1 to be approximately 2k, use a 1% resistor for best stability. c1 and cff are optional; in order to increase stability and reduce the input power line noise, cin and c1 must be placed near to vin and gnd; for output voltages greater than approximately 10v, an additional capacitor cff is required. the compensation capacitor is typically between 100 pf and 33 nf, and is wired in parallel with the output voltage setting resistor, r2. it provides additional stability for high output voltage, low input-output voltages, and/or very low esr output capacitors, such as solid tantalum capacitors. cff=1/(31*1000*r2); this capacitor type can be ceramic, plastic, silver mica, etc. (because of the unstable characteristics of ceramic capacitors made with z5u material, they are not recommended.)
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 7 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 1n5823 1n5824 1n5825 sr502 sr503 sr504 sr505 sr506 sb520 sb530 sb540 sb550 sb560 5a 50wq03 50wq04 50wq05
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 8 typical system application for 24v ~ 12v/4a version XL4005 cin 470uf/50v c1 105 r1 2k r2 28k cff 33n cout 470uf/50v d1 1n5824 l 33uh/4a +24v load 5 4 1 3 2 gnd vin fb sw en vout 12v/4a 24v ~ 12v/4a vout=0.8*(1+r2/r1) figure6. XL4005 system parameters test circuit (24v ~ 12v/4a) typical system application for 24v ~ 5v/5a XL4005 cin 470uf/50v c1 105 r1 2k r2 10.5k cff 33n cout 470uf/50v d1 1n5824 l 33uh/5a +24v load 5 3 2 vin fb sw vout 5v/5a 24v ~ 5v/5a vout=0.8*(1+r2/r1) gnd en 4 1 figure7. XL4005 system parameters test circuit (24v ~ 5v/5a)
datasheet 5a 300khz 32v buck dc to dc converter XL4005 rev 2.1 www.xlsemi.com 9 package information to263-5l
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