www.belling.com.cn 1 built-in 2a power mosfet step-down dc-dc converter b l8519 description BL8519 is a current mode pwm stepdown dcdc converter that has an internal 2a power switch. it has a wide input voltage range of 3.6vto 20v, which make it suitable forregulatingawidevarietyofpowersources. BL8519ismadeupofapwmcontrolcircuit, areferencevoltageunit,anerroramplifier,a protection circuit, chip enable circuit, and undervoltagelockoutcircuit.alowripplehigh efficiencystepdowndcdcconvertercanbe easily assembled by this ic with minimum external components: an inductor, a diode, capacitors and resistors. desired output voltage can be achieved by adjusting the valueofexternalresistors. the BL8519 has cyclebycycle current limit circuitry; current limiting provides protection against shorted output. the low current (<5ua) shutdown provides complete output disconnect, enabling easy power managementinbatterypoweredsystems. features rangeofinputvoltage:3.6v~20v builtin90m w powermosfet <5ashutdowncurrent oscillationfrequency:500khz highefficiency:90% 2.5apeakcurrentlimitcycleby cycle operatingtemperaturerange:40 ~85 demoboardavailable applications powersourceforportable communicationequipment,cameras, videoinstrumentssuchasvcrs, camcorders. powersourceforbatterypowered equipment. powersourceforhouseholdelectrical appliance typicalapplication bl blbl bl8 88 8519 519519 519
www.belling.com.cn 2 BL8519 orderinginformation BL8519 1 11 1 2 22 2 3 33 3 code description 1 11 1 temperature&rohs: c:40~85 c,pbfreerohsstd. 2 22 2 packagetype: d8:sop8 3 33 3 packingtype: tr:tape&reel(standard) pinconfiguration product classification BL8519cd8tr marking hgxx yybzz hg:product code xx:output voltage adjustable yy:lotno. b:fabcode zz:datecode pindescriptio blockdiagram pin no. symbol description 1 nc notconnected 2 vin powersupplypin 3 sw switchingnode:pwmoutputconnectiontoinduc tor. 4 gnd groundpin 5 fb pinforfeedbackvoltage 6 nc notconnected 7 ce chipenablepin(activewithh) 8 nc notconnected hgxx yybzz 1 2 3 4 5 6 7 8
www.belling.com.cn 3 BL8519 absolutemaximumrating supplyvoltage 23v swpinvoltage 25v cepinvoltage C0.3vtovin+0.3v fbpinvoltage C0.3vto6v operatingambienttemperaturerange C40cto85c storagetemperaturerange C65cto150c leadtemperature(soldering,10sec) 260c thermalresistance: ja 150c/w electricalcharacteristics (testcondition:ta=25oc,vin=12v,unlessotherwise noted.) symbol item conditions min. typ. max. unit vuvlo undervoltagelockout 3.35 3.6 v vfb feedbackvoltage 1.225 1.25 1.275 v ifb fbpinbiascurrent vfb=1.25v 150 600 na iq supplycurrent vfb=1.3v,vce=vin 2 ma quiescentcurrentin shutdown vce=0v 2 5 ua vfb/ v referenceline regulation vin=5vto20v 0.08 %/v vfb/ t feedbackvoltage temperature coefficient 40 topt 85 100 ppm/ fosc_max oscillatorfrequency vfb=1.1v 500 khz foscth frequencyshift thresholdonfbpin fsw=200k 0.44 v dmax maxdutycycle 97 % ilimit switchcurrentlimit 2.5 a rds_on staticpchannel mosfetonstate resistance 90 * m w isw switchleakage current 1 ua iceh cehinputcurrent vce=3v 6.7 15 ua icel celinputcurrent vce=0v 0.03 0.1 ua vceh cehinputvoltage vin=12v 1.8 v vcel celinputvoltage vin=12v 0.4 v
www.belling.com.cn 4 BL8519 demoboardbom no. reference type specification note 1 c1 capacitor mlcc10uf;smd0805 2 c2 capacitor mlcc10uf;smd0805 3 d1 diode ss34;40v,3a;smd 4 l1 inductor 10uh;3a;smd,shielding 5 ic1 ic BL8519;smdsop8 6 r1 resistor smd0805;30k 1% 7 r2 resistor smd0805;10k 1% layoutconsideration careful pcb layout is critical to achieving low sw itching losses and clean, stable operation. the switching power stage requires particular atten tion. if possible, mount all the power componentsononesideoftheboard,withtheirgro undterminalsasclosetooneanotheras possible. keep the highcurrent paths short, especially the distance between cin and the vin (gnd) terminals. it is essential for stable, jitterfree operation, showing as the following figure. the esrofcinshouldbesmallerenoughandthecapacit anceofcinshouldbelargeenoughfor filteringtheswitchingnoiseacrosspowerpath,a 10ufceramiccapacitorisrecommended. keep the trace connecting to sw terminal wide enou gh for heat dissipation, if possible, it is bettertoplacesomeviasconnectedtothebottomc opperforenhancement. route highspeed switching nodes, for example sw t erminal, away from sensitive analog trace(eg.fbterminal).
www.belling.com.cn 5 BL8519 demoboardmeasurement efficiency vs. load current (vout=5v) 0 10 20 30 40 50 60 70 80 90 100 0 500 1000 1500 load current(ma) efficiency(%) vin=6v vin=12v vin=18v load regulation (vout=5v) 3.5 4.0 4.5 5.0 5.5 6.0 0 500 1000 1500 load current(ma) output voltage(v) vin=6v vin=12v vin=18v ce pin bias current vs. ce pin voltage 0 10 20 30 40 50 60 70 80 0 3 6 9 12 15 18 ce pin voltage(v) ce pin bias current(ua) feedback voltage vs.supply voltage 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 5 8 11 14 17 supply voltage (v) feedback voltage (v) quiesent current vs. supply voltage (vce=0v) 0 1 2 3 4 0 3 6 9 12 15 18 supply voltage(v) quiesent current(ua) supply current vs. supply voltage (vfb=1.3v,vce=vin) 0.0 0.5 1.0 1.5 2.0 2.5 0 3 6 9 12 15 18 supply voltage(v) supply current(ma)
www.belling.com.cn 6 BL8519 frequency vs.temperature 0 100 200 300 400 500 600 700 -40 -15 10 35 60 85 temperature frequency(khz) feedback voltage vs. temperature 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 -40 -15 10 35 60 85 temperature( ? c) feedback voltage(v) transientloadingresponse ch2: output voltage ch1: output current ch1: output current ch2: output voltage
www.belling.com.cn 7 BL8519 packageline package sop8 devicesperreel 2500pcs unit mm packagespecification symbol dimension (mm) symbol dimension (mm) min nom max min nom max a - - 1.77 d 4.7 4.9 5.1 a1 0.08 0.18 0.28 e 5.8 6 6.2 a2 1.2 1.4 1.6 e1 3.7 3.9 4.1 a3 0.55 0.65 0.75 e 1.27bsc b 0.39 - 0.48 l 0.5 0.65 0.8 b1 0.38 0.41 0.43 l1 1.05bsc c 0.21 - 0.26 q 0 - 8
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