DIU6921

DIU6921 DIOO | Alldatasheet

Document overview

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Technical content

Features

 LowRDS(ON) orinternalswitches(top/bottom) 120mΩ/75mΩ,2.0A  4.5~30Vinputvoltagerange  High-efficiency,synchronous-mode  Internalsoft-start limitstheinrush current  Overcurrent protection  Thermalshutdown  Green package: TSOT23-6ispincompatible

Applications

 Portablenavigation devices  Set topboxes  PortableTVs  LCDTVs Descriptions The DIU6921 is a high-efficiency, high-frequency synchronous step-down DC-DC regulator IC capable of delivering up to 2 A output currents. The DIU6921 operates over a wide input voltage range from 4.5 V to 30 V and integrates the main switch and synchronous switch with very low RDS(ON) tominimizetheconduction loss. The DIU6921 adopts the COT architecture to achieve fast transient responses for high step-down applications and high efficiency at light loads. In addition, it operates at a pseudo-constant frequency of 700 kHz under heavy load conditions to minimize the size of the inductorandcapacitor. FunctionBlock OrderingInformation OrderingPartNo. TopMarking MSL RoHS TA Package DIU6921TST6 2UYW 3 Green -40to85°C TSOT23-6 Tape&Reel,3000

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter PinAssignments Figure1.TSOT23-6(Topview) PinDefinitions PinNo. PinName Description 1 GND Powerground. 2 SW Inductorpin.Connectthispintotheswitchingnodeofinductor. 3 VIN Powerinput. 4 FB Output feedback pin. Connect this pin to the center point of the output resistor dividertoprogram theoutputvoltage:VOUT =0.6×(1+R1/R2). AddoptionalC2(10pF~47pF)tospeedupthetransientresponse. 5 EN Enablecontrol.Pullhightoturnon.Donot float. 6 BS Bootstrap.ConnectacapacitorandaresistorbetweenSWandBSpinstoforma floatingsupplyacrossthehigh-sideswitchdriver.Recommendtouse0.1μFBS capacitor.

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter AbsoluteMaximumRatings Stresses beyond those listed under theAbsolute Maximum Rating table may cause permanent damage to the device. These are stressratingsonly and functional operationof the deviceat theseor any other conditionbeyond thoseindicatedin theoperational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect devicereliability.DIOOdoesnotrecommendexceedingthem ordesigningtoabsolutemaximumratings. Symbol Parameter Rating Unit VIN Supplyvoltage(V+ –V-) -0.3to36 V VEN ENvoltage -0.3toVIN +0.3 V VFB FBvoltage -0.3to6 V VBS BSvoltage VSW +6 V VSW SWvoltage <20ns -5to32 V >20ns -0.3to30 θJA Junction-to-ambientthermalresistance 89 °C/W θJC Junction-to-casethermalresistance 44.5 TSTG Storagetemperaturerange -65to150 °C TJ Junctiontemperaturerange 150 °C TL Leadtemperaturerange 260 °C ESD Human-bodymode(HBM) ±2000 V RecommendOperatingConditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditionsarespecifiedtoensureoptimalperformancetothedatasheetspecifications. Symbol Parameter Rating Unit VIN Supplyvoltage 4.5to30 V TJ Junctiontemperaturerange -40to125 °C TA Ambienttemperaturerange -40to85 °C

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter ElectricalCharacteristics VIN =12V,VOUT =1.2V,L=2.2μH,COUT =22μF,TA =25°C,IOUT =1A,unlessotherwisespecified. Symbol Parameter TestConditions Min Typ Max Unit VIN Inputvoltagerange 4.5 30 V IQ Quiescentcurrent IOUT =0,VFB =VREF ×105% 140 µA ISHDN Shutdowncurrent EN=0 5 10 µA VREF Feedbackreferencevoltage 0.588 0.6 0.612 V IFB(1) FBinputcurrent VFB =VIN -50 50 nA RDS(ON)(1) TopFETRON 120 mΩ RDS(ON)(1) BottomFET RON 75 mΩ ILIM BottomFET valleycurrentlimit 2 A VENH ENrisingthreshold TA =25°C 0.75 0.8 0.85 V TA =-40~ 125°C 0.69 0.8 0.91 V VENL_HYS Hysteresis 60 80 100 mV VUVLO InputUVLO threshold 4.5 V VUVLO_HYS UVLO hysteresis 500 mV fSW Switchingfrequency 700 kHz tON ONtime VIN =12V,VOUT =1.2V,IOUT =1A 145 ns MinONtime(1) 50 ns MinOFFtime(1) 100 ns tSS(1) Soft-starttime 2 ms TSD(1) Thermalshutdowntemperature 150 °C THYS(1) Thermalshutdownhysteresis 15 °C Note: (1) Guaranteedbydesign. (2) Specificationssubjecttochangewithoutnotice.

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter TypicalPerformanceCharacteristic VIN =12V,VOUT =3.3V,NoLoad Figure2.Startup fromVIN VIN =12V,VOUT =3.3V,NoLoad Figure3.ShutdownfromVIN VIN =12V,VOUT =3.3V,ILoad =2A Figure4.Startup fromVIN VIN =12V,VOUT =3.3V,ILoad =2A Figure5.ShutdownfromVIN VIN =12V,VOUT =3.3V,RLoad =1.65Ω Figure6.Startupfrom Enable VIN =12V,VOUT =3.3V,RLoad =1.65Ω Figure7.ShutdownfromEnable

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter VIN =12V,VOUT =3.3V,ILoad =0.2~2A Figure8.Load transient VIN =12V,VOUT =3.3V,ILoad =1~2A Figure9.Loadtransient VIN =12V,VOUT =3.3V,ILoad =0A Figure10.Ripple VIN =12V,VOUT =3.3V,ILoad =2A Figure11.Ripple VIN =12V,VOUT =3.3V,ILoad =2A Figure12. Shortcircuitprotection VIN =12V,VOUT =3.3V,ILoad =2A Figure13.Short circuitrecovery

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter Figure14.Efficiencyvs.Outputcurrent Figure15.Outputvoltagevs.Outputcurrent

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter TypicalApplication Operation The DIU6921 is asynchronous buck regulator IC that integrates the COT control, top and bottom switches on the same die to minimize the switching transition loss and conduction loss. With ultra-low RDS(ON) power switches and proprietary COT control, this regulator IC can achieve the highest efficiency and the highest switch frequency simultaneously to minimize the external inductor and capacitor size, thus achieving the minimumsolutionfootprint. The DIU6921 provides protection functions such as cycle-by-cycle current limiting and thermal shutdown protection.TheDIU6921willsensetheoutputvoltageconditionsforfaultprotection. ApplicationsInformation Because of the high integration in the DIU6921 IC, the application circuit based on this regulator IC is rather simple.OnlyinputcapacitorCIN,outputcapacitorCOUT,outputinductorL1,andfeedbackresistors(R1andR2) needtobeselectedforthetargetedapplicationspecifications. FeedbackresistordividersR1andR2 Choose R1 and R2 to program the proper output voltage. To minimize the power consumption under light loads, choose large resistance values for both R1 and R2. A value of between 10 kΩ and 1 MΩ is highly recommended for both resistors. If VOUT is 3.3 V, R1 = 100 kΩ is chosen, then R2 can be calculated to be 22 kΩ. R2= 1 OUT R0.6VV 0.6V  (1)

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter InputcapacitorCIN Thisripple currentthroughtheinputcapacitor iscalculated as: D)D(1II OUTCIN_RMS  (2) Tominimizethepotentialnoiseproblem,placeatypicalX5Ror better-gradeceramiccapacitorclosetotheIN andGNDpins.CareshouldbetakentominimizetheloopareaformedbyCIN,andIN/GNDpins.Inthiscase,a 10μFlowequivalentseries resistance(ESR)ceramiccapacitoris recommended. OutputcapacitorCOUT The output capacitor is selected to handle the output ripple noise requirements. Both steady-state ripple and transient requirements must be taken into consideration when selecting this capacitor. For the best performance, it is recommended to use an X5R or better grade ceramic capacitor greater than 22 µF capacitance. OutputinductorL1 Thereareseveralconsiderations inchoosingthisinductor. 1) Choosetheinductancetoprovide thedesiredripple current.Itissuggestedtochoosethe ripplecurrentto beabout40%ofthemaximumoutputcurrent.Theinductanceiscalculatedas: L= 40%If )/VV(1V MAXOUT,SW MAXIN,OUTOUT  (3) wherefswis theswitchingfrequencyandIOUT,MAX isthe maximumload current. The DIU6921 regulator IC is quite tolerant of different ripple current amplitudes. Consequently, the final choiceofinductancecanbeslightlyoffthecalculationvaluewithoutsignificantlyimpactingtheperformance. 2) The saturation current rating of the inductor must be selected to be greater than the peak inductor current under fullloadconditions. ISAT,MIN>IOUT,MAX + Lf2 )/VV(1V SW MAXIN,OUTOUT  (4)

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter 3) The DCR of the inductor and the core loss at the switching frequency must be low enough to achieve the desired efficiency requirement. It is desirable to choose an inductor with DCR < 50 mΩ to achieve good overall efficiency. Externalbootstrap cap This capacitor provides the gate driver voltage for internal high-side MOSFET. A 100 nF low ESR ceramic capacitorconnectedbetweentheBSpin andSWpin isrecommended. Loadtransientconsiderations The DIU6921 regulator IC integrates the compensation components to achieve good stability and fast transient responses.In someapplications, adding a 22 pF ceramiccap in parallel with R1 mayfurther speed uptheloadtransientresponses andisthus recommendedforapplicationswith largeloadtransient. Layoutdesign The layout design of the DIU6921 regulator is relatively simple. For the best efficiency and minimum noise problems,placethefollowingcomponentsclosetotheIC:CIN,L1,R1,and R2. 1) Itis desirable tomaximize the PCB copper areaconnectedto the GNDpin to achieve the bestthermal and noiseperformance.Iftheboardspaceallows,agroundplaneishighlydesirable. 2) CIN mustbeclosetoINandGNDpins.TheloopareaformedbyCIN andGNDmustbeminimized. 3) ThePCBcopperareaassociatedwiththeSW pinmustbeminimized toavoid thepotentialnoiseproblem. 4) The components R1 and R2, and the trace connecting to the FB pin must NOT be adjacent to the SW net onthePCBlayouttoavoidthenoiseproblem. 5) Ifthe systemchip interfacingwith the ENpin has ahigh impedancestate atshutdownmodeand the INpin is connected directly to a power source such as a Li-Ion battery, it is desirable to add a pull-down 1 MΩ resistor between the EN and GND pins to prevent the noise from falsely turning on the regulator at shutdownmode.

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter PhysicalDimensions:TSOT23-6 CommonDimensions (Unitsofmeasure=millimeter) Symbol Min Nom Max A - - 0.90 A1 0 - 0.15 A2 0.65 0.75 0.85 A3 0.35 0.40 0.45 b 0.36 - 0.50 b1 0.36 0.38 0.45 c 0.14 - 0.20 c1 0.14 0.15 0.16 D 2.85 2.95 3.05 E 2.60 2.80 3.00 E1 1.60 1.65 1.70 e 0.90 0.95 1.00 e1 1.80 1.90 2.00 L 0.30 0.45 0.60 L1 0.575REF L2 0.25BSC R - - 0.25 R1 - - 0.25 Θ 0° - 8° Θ1 3° 5° 7° Θ2 10° 12° 14°

www.dioo.com ©2024DIOOMICROCIRCUITS CO.,LTD DIU6921•Rev.1.1 High-Efficiency2A,30VInputSynchronousStep-DownConverter CONTACTUS Diooisaprofessionaldesignandsalescorporationforhigh-qualityandperformanceanalogsemiconductors.Thecompanyfocuseson industry markets, such as cell phones, handheld products, laptops, medical equipment, and so on. Dioo’s product families include analog signal processing and amplifying, LED drivers, and charger ICs. Go to http://www.dioo.com for a complete list of Dioo product families. Foradditionalproductinformationorfulldatasheet,pleasecontactoursalesdepartmentorrepresentatives.