TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 4.5V to 18V Input, 3-A Synchronous Step-Down Converter with Eco-mode™ CheckforSamples:TPS54326 FEATURES DESCRIPTION 1 • D-CAP2™ModeEnablesFastTransient The TPS54326 is an adaptive on-time D-CAP2™ 23 mode synchronous buck converter. The TPS54326 Response enables system designers to complete the suite of • LowOutputRippleandAllowsCeramicOutput various end equipment’s power bus regulators with a Capacitor cost effective, low component count, low standby • WideV InputVoltageRange:4.5Vto18V current solution. The main control loop for the CC TPS54326 uses the D-CAP2™ mode control which • WideV InputVoltageRange:2Vto18V IN provides a fast transient response with no external • OutputVoltageRange:0.76Vto5.5V components. The adoptive on-time control supports • HighlyEfficientIntegratedFET’sOptimized seamless operation between PWM mode at heavy forLowerDutyCycleApplications load condition and reduced frequency Eco-mode™ -120mΩ(HighSide)and70mΩ (LowSide) operationatlightloadforhighefficiency. • HighEfficiency,lessthan10μAatShutdown The TPS54326 also has a proprietary circuit that • Auto-SkipEco-mode™forHighEfficiencyat enables the device to adapt to both low equivalent series resistance (ESR) output capacitors, such as LightLoad POSCAP or SP-CAP, and ultra-low ESR ceramic • HighInitialBandgapReferenceAccuracy capacitors. The device operates from 4.5-V to 18-V • AdjustableSoftStart V input , and from 2-V to 18-V VIN input power CC • Pre-BiasedSoftStart supply voltage. The output voltage can be programmed between 0.76 V and 5.5 V. The device • 700-kHzSwitchingFrequency(f ) SW also features an adjustable slow start time and a • Cycle-By-CycleOvercurrentLimit power good function. The TPS54326 is available in • PowerGoodOutput the 14 pin HTSSOP or 16 pin QFN package, and designedtooperatefrom–40°Cto85°C. APPLICATIONS • WideRangeofApplicationsforLowVoltage System – DigitalTVPowerSupply – HighDefinitionBlu-rayDisc™Players – NetworkingHomeTerminal – DigitalSetTopBox(STB) VOUT(50 mV/div) IOUT(1A/div) 100ms/div 1 Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsof TexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet. D-CAP2,Eco-mode,PowerPADaretrademarksofTexasInstruments. 2 Blu-rayDiscisatrademarkofBlu-rayDiscAssociation. 3 PRODUCTIONDATAinformationiscurrentasofpublicationdate. Copyright©2009–2012,TexasInstrumentsIncorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarilyincludetestingofallparameters.

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriateprecautions.Failuretoobserveproperhandlingandinstallationprocedurescancausedamage. ESDdamagecanrangefromsubtleperformancedegradationtocompletedevicefailure.Precisionintegratedcircuitsmaybemore susceptibletodamagebecauseverysmallparametricchangescouldcausethedevicenottomeetitspublishedspecifications. ORDERINGINFORMATION(1) T PACKAGE(2) (3) ORDERABLEPARTNUMBER PIN TRANSPORT A MEDIA PowerPAD™ TPS54326PWP Tube 14 (HTSSOP)–PWP TPS54326PWPR TapeandReel –40°Cto85°C TPS54326RGTT TapeandReel PlasticQuadFlatPack(QFN) 16 TPS54326RGTR TapeandReel (1) Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orseetheTI websiteatwww.ti.com. (2) Packagedrawings,thermaldata,andsymbolizationareavailableatwww.ti.com/packaging. (3) AllpackageoptionshaveCuNIPDAUlead/ballfinish. ABSOLUTE MAXIMUM RATINGS overoperatingfree-airtemperaturerange(unlessotherwisenoted) (1) VALUE UNIT V ,V ,EN –0.3to20 V IN CC V –0.3to26 V BST V (vsSW1,SW2) –0.3to6.5 V BST V Inputvoltagerange I V ,V ,SS,PG –0.3to6.5 V FB O SW1,SW2 –2to20 V SW1,SW2(10nstransient) –3to20 V V –0.3to6.5 V REG5 V Outputvoltagerange O P ,P –0.3to0.3 V GND1 GND2 V VoltagefromGNDtoPOWERPAD –0.2to0.2 V diff HumanBodyModel(HBM) 2 kV ESDrating Electrostaticdischarge ChargedDeviceModel(CDM) 500 V T Operatingjunctiontemperature –40to150 °C J T Storagetemperature –55to150 °C stg (1) Stressesbeyondthoselistedunderabsolutemaximumratingsmaycausepermanentdamagetothedevice.Thesearestressratings only,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderrecommendedoperating conditionsisnotimplied.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability. THERMAL INFORMATION TPS54326 TPS54326 THERMALMETRIC(1) PWP RGT UNITS 14PINS 16PINS θ Junction-to-ambientthermalresistance 55.6 46.1 JA θ Junction-to-case(top)thermalresistance 51.3 58.1 JCtop θ Junction-to-boardthermalresistance 26.4 18.8 JB °C/W ψ Junction-to-topcharacterizationparameter 1.8 1.3 JT ψ Junction-to-boardcharacterizationparameter 20.6 18.8 JB θ Junction-to-case(bottom)thermalresistance 4.3 4.8 JCbot (1) Formoreinformationabouttraditionalandnewthermalmetrics,seetheICPackageThermalMetricsapplicationreport,SPRA953. 2 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 RECOMMENDED OPERATING CONDITIONS overoperatingfree-airtemperaturerange(unlessotherwisenoted) MIN MAX UNIT V Supplyinputvoltagerange 4.5 18 V CC V Powerinputvoltagerange 2 18 V IN V –0.1 24 BST V (vsSW1,SW2) –0.1 5.7 BST SS,PG –0.1 5.7 EN –0.1 18 V Inputvoltagerange V I V ,V –0.1 5.5 O FB SW1,SW2 –1.8 18 SW1,SW2(10nstransient) –3 18 P ,P –0.1 0.1 GND1 GND2 V Outputvoltagerange V –0.1 5.7 V O REG5 I Outputcurrentrange I 0 10 mA O VREG5 T Operatingfree-airtemperature –40 85 °C A T Operatingjunctiontemperature –40 125 °C J ELECTRICAL CHARACTERISTICS overoperatingfree-airtemperaturerange,V ,V =12V(unlessotherwisenoted) CC IN PARAMETER TESTCONDITIONS MIN TYP MAX UNIT SUPPLYCURRENT Operating-non-switchingsupply V current,T =25°C,EN=5V, I CC A 850 1300 μA VCC current V =0.8V FB I Shutdownsupplycurrent V current,T =25°C,EN=0V 1.8 10 μA VCCSDN CC A LOGICTHRESHOLD V ENhigh-levelinputvoltage EN 1.5 V ENH V ENlow-levelinputvoltage EN 0.4 V ENL V VOLTAGEANDDISCHARGERESISTANCE FB V Voltagelightloadmode T =25°C,V =1.05V,I =10mA 771 mV FB A O O T =25°C,V =1.05V 757 765 773 A O V Thresholdvoltage,continuousmode T =0°Cto85°C,V =1.05V(1) 753 777 mV FB A O T =-40°Cto85°C,V =1.05V(1) 751 779 A O I Inputcurrent V =0.8V,T =25°C 0 ±0.1 μA VFB FB A R V dischargeresistance EN=0V,V =0.5V,T =25°C 50 100 Ω Dischg O O A V OUTPUT REG5 T =25°C,6V<V <18V, V Outputvoltage A CC 5.3 5.5 5.7 V VREG5 0<I <5mA VREG5 V Lineregulation 6V<V <18V,I =5mA 20 mV LN5 CC VREG5 V Loadregulation 0mA<I <5mA 100 mV LD5 VREG5 I Outputcurrent V =6V,V =4V,T =25°C 70 mA VREG5 CC REG5 A MOSFET R Highsideswitchresistance 25°C,V -SW1,SW2=5.5V 120 mΩ DS(on)h BST R Lowsideswitchresistance 25°C 70 mΩ DS(on)l CURRENTLIMIT I Currentlimit L =1.5µH (1) 3.5 4.1 5.5 A ocl OUT THERMALSHUTDOWN Shutdowntemperature (1) 150 T Thermalshutdownthreshold °C SDN Hysteresis (1) 25 (1) SpecifiedbyDesign(notproductiontested). Copyright©2009–2012,TexasInstrumentsIncorporated 3 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com ELECTRICAL CHARACTERISTICS (continued) overoperatingfree-airtemperaturerange,V ,V =12V(unlessotherwisenoted) CC IN PARAMETER TESTCONDITIONS MIN TYP MAX UNIT ON-TIMETIMERCONTROL t Ontime V =12V,V =1.05V 145 ns ON IN O t Minimumofftime T =25°C,V =0.7V 260 310 ns OFF(MIN) A FB SOFTSTART I SSchargecurrent V =0V 1.4 2 2.6 μA SSC SS I SSdischargecurrent V =0.5V 0.1 0.2 mA SSD SS POWERGOOD V rising(good) 85 90 95 FB V Threshold % THPG V falling(fault) 85 FB I Sinkcurrent PG=0.5V 2.5 5 mA PG OUTPUTUNDERVOLTAGEANDOVERVOLTAGEPROTECTION V OutputOVPtripthreshold OVPdetect 115 120 125 % OVP t OutputOVPpropdelay 5 μs OVPDEL UVPdetect 65 70 75 V OutputUVPtripthreshold % UVP Hysteresis 10 t OutputUVPdelay 0.25 ms UVPDEL t OutputUVPenabledelay Relativetosoft-starttime x1.7 UVPEN UVLO WakeupV voltage 3.55 3.8 4.05 REG5 UVLO Threshold V HysteresisV voltage 0.23 0.35 0.47 REG5 DEVICE INFORMATION PWPPACKAGE (TOPVIEW) VO 1 14 VCC VFB 2 13 VIN VREG5 3 12VBST SS 4 POWERPAD 11 SW2 GND 5 10 SW1 PG 6 9 PGND2 EN 7 8 PGND1 4 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 RGTPACKAGE (TOPVIEW) C N2 N1 VO VC VI VI 16 15 14 13 VFB 1 12 VBST VREG5 2 11 SW3 EXPOSED THERMAL PAD SS 3 10 SW2 GND 4 9 SW1 5 6 7 8 G N D1 D2 P E N N G G P P PINFUNCTIONS PIN DESCRIPTION NAME PWP14 RGT16 VO 1 16 Connecttooutputofconverter.ThispinisusedforOn-TimeAdjustment. VFB 2 1 Converterfeedbackinput.Connectwithfeedbackresistordivider. VREG5 3 2 5.5Vpowersupplyoutput.Acapacitor(typical1μF)shouldbeconnectedtoGND. SS 4 3 Soft-startcontrol.AexternalcapacitorshouldbeconnectedtoGND. GND 5 4 Signalgroundpin PG 6 5 Opendrainpowergoodoutput EN 7 6 Enablecontrolinput PGND1, Groundreturnsforlow-sideMOSFET.Alsoserveasinputsofcurrentcomparators.ConnectPGND 8,9 7,8 PGND2 andGNDstronglytogetherneartheIC. Switchnodeconnectionbetweenhigh-sideNFETandlow-sideNFET.Alsoserveasinputstocurrent SW1,SW2 10,11 9,10,11 comparators. Supplyinputforhigh-sideNFETgatedriver(boostterminal).Connectcapacitorfromthispinto VBST 12 12 respectiveSW1,SW2terminals.AninternalPNdiodeisconnectedbetweenVREG5toVBSTpin. VIN 13 13,14 PowerinputandconnectedtohighsideNFETdrain VCC 14 15 Supplyinputfor5Vinternallinearregulatorforthecontrolcircuitry Exposed Thermal Back Back Thermalpadofthepackage.Mustbesolderedtoachieveappropriatedissipation.Shouldbe Pador side side connectedtoPGND. PowerPAD ™ Copyright©2009–2012,TexasInstrumentsIncorporated 5 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com FunctionalBlockDiagram -30% UV 14 VCC VIN VIN OV 13 1 VO +20% VREG5 VBST Control logic 12 Ref SS 1shot SW VO 2 11 VFB XCON 10 VREG5 SGND VREG5 Ceramic 3 Capacitor SS 1mF 4 9 8 PGND Softstart SW PGND SS ZC PGND 5 GND SW OCP SGND Ref PGND VCC 6 PG -10% UV VREG5 OV Protection UVLO UVLO Logic EN EN 7 TSD Logic REF Ref A. BlockdiagramshownisforPWP14pinpackage.QFN16pinpackageblockdiagramisidenticalexceptforpinout. OVERVIEW The TPS54326 is a 3-A synchronous step-down (buck) converter with two integrated N-channel MOSFETs and Auto-Skip Eco-Mode™ to improve light lode efficiency . It operates using D-CAP2™ mode control. The fast transient response of D-CAP2™ control reduces the output capacitance required to meet a specific level of performance. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and specialpolymertypes. DETAILED DESCRIPTION PWMOperation The main control loop of the TPS54326 is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ mode control. D-CAP2™ mode control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with bothlowESRandceramicoutputcapacitors.Itisstableevenwithvirtuallynorippleattheoutput. 6 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 At the beginning of each cycle, the high-side MOSFET is turned on. This MOSFET is turned off after internal one shot timer expires. This one shot timer is set by the converter input voltage ,V , and the output voltage ,V , to IN O maintain a pseudo-fixed frequency over the input voltage range, hence it is called adaptive on-time control. The one-shot timer is reset and the high-side MOSFET is turned on again when the feedback voltage falls below the reference voltage. An internal ramp is added to the reference voltage to simulate output ripple, eliminating the needforESRinducedoutputripplefromD-CAP2™modecontrol. PWMFrequencyandAdaptiveOn-TimeControl TPS54326 uses an adaptive on-time control scheme and does not have a dedicated on board oscillator. The TPS54326 runs with a pseudo-constant frequency of 700 kHz by using the input voltage and output voltage to set the on-time one-shot timer. The on-time is inversely proportional to the input voltage and proportional to the outputvoltage.Theactualfrequencymayvaryfrom700kHzdependingontheofftime,whichisendedwhenthe fedbackportionoftheoutputvoltagefallstotheV thresholdvoltage. FB Auto-SkipEco-Mode™Control The TPS54326 is designed with Auto-Skip Eco-Mode™ to increase light load efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to point that its rippled valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when its zero inductor current is detected. As the load current further decreases the converter run into discontinuous conduction mode. The on-time is kept almost the same as is was in the continuous conduction mode so that it takes longer time to discharge the output capacitor with smaller load current to the level of the reference voltage. The transition point to the light load operation I currentcanbecalculatedinEquation1. OUT(LL) 1 (V - V )·V I =-·-IN OUT OUT OUT(LL) 2·L·fws V IN (1) SoftStartandPre-BiasedSoftStart The soft start function is adjustable. When the EN pin becomes high, 2-μA current begins charging the capacitor which is connected from the SS pin to GND. Smooth control of the output voltage is maintained during start up. The equation for the slow start time is shown in Equation 2. VFB voltage is 0.765 V and SS pin source current is 2μA. C6(nF)•Vref C6(nF)•0.765 Tss(ms) = − = − Iss(µA) 2 (2) A unique circuit to prevent current from being pulled from the output during startup if the output is pre-biased. When the soft-start commands a voltage higher than the pre-bias level (internal soft start becomes greater than feedback voltage V ), the controller slowly activates synchronous rectification by starting the first low side FET FB gate driver pulses with a narrow on-time. It then increments that on-time on a cycle-by-cycle basis until it coincides with the time dictated by (1-D), where D is the duty cycle of the converter. This scheme prevents the initial sinking of the pre-bias output, and ensure that the out voltage (VO) starts and ramps up smoothly into regulationandthecontrolloopisgiventimetotransitionfrompre-biasedstart-uptonormalmodeoperation. PowerGood The power good function is activated after soft start has finished. The power good function becomes active after 1.7 times soft-start time. When the output voltage is within –10% of the target value, internal comparators detect power good state and the power good signal becomes high. Rpg resister value, which is connected between PG and VREG5, is required from 20kΩ to 150kΩ. If the feedback voltage goes under 15% of the target value, the powergoodsignalbecomeslowaftera10msinternaldelay. OutputDischargeControl TPS54326 discharges the output when EN is low, or the controller is turned off by the protection functions (OVP, UVP, UVLO and thermal shutdown). The output is discharged by an internal 50-Ω MOSFET which is connected from VO to PGND. The internal low-side MOSFET is not turned on during the output discharge operation to avoidthepossibilityofcausingnegativevoltageattheoutput. Copyright©2009–2012,TexasInstrumentsIncorporated 7 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com CurrentProtection The output over-current protection (OCP) is implemented using a cycle-by-cycle valley detect control circuit. The switch current is monitored by measuring the low-side FET switch voltage between the SW pin and GND. This voltage is proportional to the switch current. To improve accuracy, the voltage sensing is temperature compensated. During the on time of the high-side FET switch, the switch current increases at a linear rate determined by Vin, Vout, the on-time and the output inductor value. During the on time of the low-side FET switch, this current decreases linearly. The average value of the switch current is the load current Iout. If the measured voltage is above the voltage proportional to the current limit, Then , the device constantly monitors the low-side FET switch voltage,whichisproportionaltotheswitchcurrent,duringthelow-sideon-time. The converter maintains the low-side switch on until the measured voltage is below the voltage corresponding to the current limit at which time the switching cycle is terminated and a new switching cycle begins. In subsequent switchingcycles,theon-timeissettoafixedvalueandthecurrentismonitoredinthesamemanner. There are some important considerations for this type of over-current protection. The load current one half of the peak-to-peak inductor current higher than the over-current threshold. Also when the current is being limited, the output voltage tends to fall as the demanded load current may be higher than the current available from the converter. This may cause the output under-voltage protection circuit to be activated. When the over current conditionisremoved,theoutputvoltagewillreturntotheregulatedvalue.Thisprotectionisnon-latching. Over/UndervoltageProtection The TPS54326 detects over and undervoltage conditions by monitoring the feedback voltage (VFB). This function is enabled after approximately 1.7 times the soft-start time. When the feedback voltage becomes higher than 120% of the target voltage, the OVP comparator output goes high and the circuit latches the high-side MOSFET driver turns off and the low-side MOSFET turns on. When the feedback voltage becomes lower than 70% of the target voltage, the UVP comparator output goes high and an internal UVP delay counter begins. After 250μs,thedevicelatchesoffbothinternaltopandbottomMOSFET. UVLOProtection Undervoltage lock out protection (UVLO) monitors the voltage of the V pin. When the V voltage is lower REG5 REG5 thanUVLOthresholdvoltage,theTPS54326isshutoff.Thisisprotectionisnon-latching. ThermalShutdown Thermal protection is self-activating. If the junction temperature exceeds the threshold value (typically 150°C), theTPS54326shutsoff.Thisprotectionisnon-latching. 8 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 TYPICAL CHARACTERISTICS VIN=12V,T =25°C(unlessotherwisenoted) A spacer 1200 8 1000 6 A A800 m nt -m ent - urre600 Curr 4 C n y w pl o Sup400 hutd S 2 200 0 0 -50 0 50 100 150 -50 0 50 100 150 TJ- Junction Temperature - °C TJ- Junction Temperature - °C Figure1.V SUPPLYCURRENTvs.JUNCTION Figure2.V SHUTDOWNCURRENTvs.JUNCTION CC CC TEMPERATURE TEMPERATURE 1.1 1.1 1.075 1.075 IO= 10 mA V = 18 V V I V ge - ge - Output Volta 1.05 VI= 12 V VI= 5 V Output Volta 1.05 IO= 1 mA V- O1.025 V- O1.025 1 1 0 0.5 1 1.5 2 2.5 3 0 5 10 15 20 IO- Output Current -A VI- Input Voltage - V Figure3.1.05-VOUTPUTVOLTAGEvs.OUTPUT Figure4.1.05-VOUTPUTVOLTAGEvs.INPUTVOLTAGE CURRENT Copyright©2009–2012,TexasInstrumentsIncorporated 9 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com TYPICAL CHARACTERISTICS (continued) VIN=12V,T =25°C(unlessotherwisenoted) A spacer V (50 mV/div) OUT EN (10 V/div) V (0.5 V/div) OUT I (1A/div) OUT PG (5 V/div) 100ms/div 400ms/div Figure5.1.05-V,0-ATO3-ALOADTRANSIERESPONSE Figure6.START-UPWAVEFORM 100 100 VO= 3.3 V VO= 3.3 V 20 80 80 V = 2.5 V % VO= 1.8 V O % 60 VO= 1.8 V ncy - 60 ncy - VO= 2.5 e e ci ci Effi Effi 40 40 20 20 0 0 0 0.5 1 1.5 2 2.5 3 0.001 0.01 0.1 IO- Output Current -A IO- Output Current -A Figure7.EFFICIENCYvs.OUTPUTCURRENT Figure8.LIGHTLOADEFFICIENCYvs.OUTPUT (V =12V) CURRENT IN 10 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 TYPICAL CHARACTERISTICS (continued) VIN=12V,T =25°C(unlessotherwisenoted) A spacer 900 900 800 V = 1.8 V z z700 O H800 H k k y - y - 600 c c n n eque VO= 1.8 V eque500 VO= 2.5 V Fr700 Fr g g 400 n n hi hi c c wit wit300 - Sw600 VO= 3.3 V - Sw200 fs fs 100 500 0 0 5 10 15 20 0.001 0.01 0.1 V - Input Voltage - V I - Output Current -A I O Figure9.SWITCHINGFREQUENCYvsINPUTVOLTAGE Figure10.SWITCHINGFREQUENCYvsOUTPUT CURRENT V (50 mV/div) IN V (10 mV/div) O SW (5 V/div) SW (5 V/div) 400 ns/div 400 ns/div Figure11.VOLTAGERIPPLEAtOUTPUT Figure12.VOLTAGERIPPLEAtINPUT Copyright©2009–2012,TexasInstrumentsIncorporated 11 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com DESIGN GUIDE StepByStepDesignProcedure Tobeginthedesignprocess,thefollowingapplicationparametersmustbeknown: • Inputvoltagerange • Outputvoltage • Outputcurrent • Outputvoltageripple • Inputvoltageripple Figure13showstheschematicdiagramforthisdesignexample. Figure13. SchematicDiagram OutputVoltageResistorsSelection The output voltage is set with a resistor divider from the output node to the VFB pin. It is recommended to use 1%toleranceorbetterdividerresistors.StartbyusingEquation3andEquation4tocalculateV . OUT To improve efficiency at light loads consider using larger value resistors, too high of resistance is more susceptibletonoiseandvoltageerrorsfromtheVFBinputcurrentaremorenoticeable. Foroutputvoltagefrom0.76Vto2.5V: ( R1) VOUT=0.765 • 1 + −R2 (3) Foroutputvoltageover2.5V: VOUT=(0.763 + 0.0017 •VOUT)•(1 + −RR21) (4) Where: V =TargetV voltage OUT_SET OUT 12 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 OutputFilterSelection TheoutputfilterusedwiththeTPS54326isanLCcircuit.ThisLCfilterhasdoublepoleat: 1 F = P 2p L ´C OUT OUT (5) At low frequencies, the overall loop gain is set by the output set-point resistor divider network and the internal gain of the TPS54326. The low frequency phase is 180 degrees. At the output filter pole frequency, the gain rolls off at a –40 dB per decade rate and the phase drops rapidly. D-CAP2™ introduces a high frequency zero that reduces the gain roll off to -20 dB per decade and increases the phase to 90 degrees one decade above the zero frequency. The inductor and capacitor selected for the output filter must be selected so that the double pole of Equation 5 is located below the high frequency zero but close enough that the phase boost provided by the high frequency zero provides adequate phase margin for a stable circuit. To meet this requirement use the valuesrecommendedinTable1. Table1.RecommendedComponentValues OUTPUTVOLTAGE R1(kΩ) R2(kΩ) C4(pF)(1) L1(µH) C4+C5(µF) (V) 1 6.81 22.1 1.5 22-68 1.05 8.25 22.1 1.5 22-68 1.2 12.7 22.1 1.5 22-68 1.8 30.1 22.1 10-47 2.2 22-68 2.5 49.9 22.1 10-47 2.2 22-68 3.3 73.2 22.1 10-47 2.2 22-68 5 121 22.1 10-47 3.3 22-68 (1) Optional For higher output voltages at or above 1.8 V, additional phase boost can be achieved by adding a feed forward capacitor(C4)inparallelwithR1. The inductor peak-to-peak ripple current, peak current, and RMS current are calculated using Equation 6, Equation 7, and Equation 8. The inductor saturation current rating must be greater than the calculated peak current and the RMS or heating current rating must be greater than the calculated RMS current. Use 700 kHz for f . SW V V - V Ilp - p = OUT • IN (max) OUT V L •f IN (max) O SW (6) Ilp - p I = I +  lpeak O 2 (7) − √ 1 I = I 2+ −Ilp - p2 Lo(RMS) O 12 (8) For this design example, the calculated peak current is 3.47 A and the calculated RMS current is 3.01 A. The inductor used is a TDK SPM6530-1R5M100 with a peak current rating of 11.5 A and an RMS current rating of 11 A. The capacitor value and ESR determines the amount of output voltage ripple. The TPS54326 is intended for use with ceramic or other low ESR capacitors. Recommended values range from 22 µF to 68 µF. Use Equation 9 to determinetherequiredRMScurrentratingfortheoutputcapacitor. V • (V - V ) I =−−OUT IN OUT CO(RMS) √12 •V •L •f IN O SW (9) For this design two TDK C3216X5R0J226M 22 µF output capacitors are used. The typical ESR is 2 mΩ each. ThecalculatedRMScurrentis0.271Aandeachoutputcapacitorisratedfor4A. Copyright©2009–2012,TexasInstrumentsIncorporated 13 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com InputCapacitorSelection The TPS54326 requires an input decoupling capacitor and a bulk capacitor is needed depending on the application. A ceramic capacitor over 10 μF is recommended for the decoupling capacitor. An additional 0.1 µF capacitor from pin 14 to ground is recommended. The capacitor voltage rating needs to be greater than the maximuminputvoltage. BootstrapCapacitorSelection A 0.1 µF ceramic capacitor must be connected between the VBST to SW pin for proper operation. It is recommendedtouseaceramiccapacitor. VREG5CapacitorSelection A 1.0 µF ceramic capacitor must be connected between the VREG5 to GND pin for proper operation. It is recommendedtouseaceramiccapacitor. THERMAL INFORMATION The PWP 14 pin package incorporates an exposed PowerPAD™ and the QFN 16 pin package incorporates a similarexposedthermalpad.Theseexposedthermalpadsaredesignedtobeconnectedtoanexternalheatsink. Thethermalpadmustbesoldereddirectlytotheprintedboard(PCB).Aftersoldering,thePCBcanbeusedasa heatsink. In addition, through the use of thermal vias, the thermal pad can be attached directly to the appropriate copper plane shown in the electrical schematic for the device, or alternatively, can be attached to a special heatsinkstructuredesignedintothePCB.Thisdesignoptimizestheheattransferfromtheintegratedcircuit(IC). For additional information on the PowerPAD™ package and how to use the advantage of its heat dissipating abilities, see the Technical Brief, PowerPAD™ Thermally Enhanced Package, Texas Instruments Literature No. SLMA002andApplicationBrief,PowerPAD™MadeEasy,TexasInstrumentsLiteratureNo.SLMA004. The exposed thermal pad dimensions for the PWP 14 pin and QFN 16 pin packages are shown in the Thermal PadMechanicalDatasectionofthisdatasheet. 14 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 LAYOUT CONSIDERATIONS The following layout guidelines are provided using the PWP 14 pin package as an example. The general guidelines and routing are also applicable to the QFN 16 pin package. Allowance should be made for the differencesinthepackagepinconfigurations. 1. Keeptheinputswitchingcurrentloopassmallaspossible. 2. Keep the SW node as physically small and short as possible to minimize parasitic capacitance and inductance and to minimize radiated emissions. Kelvin connections should be brought from the output to the feedbackpinofthedevice. 3. Keepanalogandnon-switchingcomponentsawayfromswitchingcomponents. 4. Makeasinglepointconnectionfromthesignalgroundtopowerground. 5. Donotallowswitchingcurrenttoflowunderthedevice. 6. KeepthepatternlinesforVINandPGNDbroad. 7. ExposedpadofdevicemustbeconnectedtoPGNDwithsolder. 8. VREG5capacitorshouldbeplacednearthedevice,andconnectedPGND. 9. OutputcapacitorshouldbeconnectedtoabroadpatternofthePGND. 10. Voltagefeedbackloopshouldbeasshortaspossible,andpreferablywithgroundshield. 11. LowerresistorofthevoltagedividerwhichisconnectedtotheVFBpinshouldbetiedtoSGND. 12. ProvidingsufficientviaispreferableforVIN,SWandPGNDconnection. 13. PCBpatternforVIN,SW,andPGNDshouldbeasbroadaspossible. 14. IfVINandVCCisshorted,VINandVCCpatternsneedtobeconnectedwithbroadpatternlines. 15. VINCapacitorshouldbeplacedasnearaspossibletothedevice. VCC INPUT BYPASS CAPACITOR Additional VCC Thermal VIN Vias VIN INPUT BYPASS FREEESDISBTAOCRKS VOUT VCC CAPACITOR VFB VIN BOOST VREG5 VBST CAPACITOR VOUT BIAS SS SW1 CAP GND SW2 OUTPUT INDUCTOR OUTPUT SLOW PG EXPOSED PGND1 FILTER START POWERPAD CAPACITOR CAP EN AREA PGND2 Connection to POWER GROUND on internal or ANALOG Additional bottom layer GROUND Thermal TRACE Vias To Enable Control POWER GROUND VIAto Ground Plane Etch on Bottom Layer or Under Component Figure14. TPS54326Layout Copyright©2009–2012,TexasInstrumentsIncorporated 15 ProductFolderLink(s):TPS54326

TPS54326 SLVSA13E–OCTOBER2009–REVISEDJUNE2012 www.ti.com REVISION HISTORY ChangesfromOriginal(October2009)toRevisionA Page • ChangedthedatasheetFrom:ProductPreviewTo:ProductionData ................................................................................ 1 ChangesfromRevisionA(October2009)toRevisionB Page • ChangedthetitletoincludeEco-Mode................................................................................................................................. 1 • ChangedfeaturesbullettoreferenceEco-mode .................................................................................................................. 1 • AddedEco-ModetexttotheDESCRIPTION ....................................................................................................................... 1 • AddedtheQFNpackagetotheDESCRIPTION .................................................................................................................. 1 • AddedtheQFNpackagetotheORDERINGINFORMATIONtable .................................................................................... 2 • AddedtheRGTPACKAGEdrawing ..................................................................................................................................... 5 • AddedtheRGT16pincolumntothePINFUNCTIONStable ............................................................................................. 5 • ChangedFunctionalBlockDiagram ..................................................................................................................................... 6 • AddedtextNotetotheFunctionalBlockDiagram ................................................................................................................ 6 • AddedEco-ModetexttotheOVERVIEWsection ................................................................................................................ 6 • ChangedsectiontitleFrom:LightLoadModeControlTo:LightLoadEco-ModeControl ................................................... 7 • AddedEco-ModetotextinLightLoadEco-ModeControlsection ....................................................................................... 7 • AddedNote1toTable1..................................................................................................................................................... 13 • AddedtexttotheTHERMALINFORMATIONsectionfortheQFNpackage. .................................................................... 14 • Deletedfigure"ThermalPadDimensions" ......................................................................................................................... 14 ChangesfromRevisionB(June2010)toRevisionC Page • ChangedTPS54326PWPRtapeandreelquantityFrom:3000To:2000 ............................................................................ 2 • AddedV ,V =12VtotheconditionstatementintheElectricalCharacteristicstable ..................................................... 3 CC IN ChangesfromRevisionC(October2010)toRevisionD Page • DeletedquantitiesfromTransportMediacolumn ................................................................................................................. 2 • Changedfrom–45°Cto85°Cto–40°Cto85°CinOrderingInformation ............................................................................ 2 • AddedThermalInformationtable ......................................................................................................................................... 2 • AddedI rowtotheROCtable ............................................................................................................................................. 3 O • ChangedFunctionalBlockDiagram ..................................................................................................................................... 6 • ChangedsectiontitleFrom:LightLoadEco-ModeControlTo:Auto-SkipEco-ModeControl............................................. 7 • AddedAuto-SkiptotextinAuto-SkipEco-ModeControlsection ......................................................................................... 7 • ChangedEquation1 ............................................................................................................................................................. 7 • ChangedPowerGoodsectiontext ....................................................................................................................................... 7 • ChangedCurrentProtectionsectiontext .............................................................................................................................. 8 • ChangedDesignGuideinformation.................................................................................................................................... 12 • ChangedTable1C4values ............................................................................................................................................... 13 16 Copyright©2009–2012,TexasInstrumentsIncorporated ProductFolderLink(s):TPS54326

TPS54326 www.ti.com SLVSA13E–OCTOBER2009–REVISEDJUNE2012 ChangesfromRevisionD(February2011)toRevisionE Page • RemovedSWIFTfromthedatasheettilte ........................................................................................................................... 1 • ChangedV minvalueinELECTRICALCHARACTERISTICSfrom2Vto1.5V ............................................................ 3 ENH • ChangedTable1lastcolumnheadingfromC8+C9toC4+C5...................................................................................... 13 • DeletedtextfromtheInputCapacitorSelectionsetion-"toimprovethestabilityoftheover-currentlimitfunction."........ 14 Copyright©2009–2012,TexasInstrumentsIncorporated 17 ProductFolderLink(s):TPS54326

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) TPS54326PWP ACTIVE HTSSOP PWP 14 90 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 PS54326 & no Sb/Br) TPS54326PWPR ACTIVE HTSSOP PWP 14 2000 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 PS54326 & no Sb/Br) TPS54326RGTR ACTIVE VQFN RGT 16 3000 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 54326 & no Sb/Br) TPS54326RGTT ACTIVE VQFN RGT 16 250 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 54326 & no Sb/Br) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and Addendum-Page 1

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 7-Nov-2019 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1 Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant (mm) W1(mm) TPS54326PWPR HTSSOP PWP 14 2000 330.0 12.4 6.9 5.6 1.6 8.0 12.0 Q1 TPS54326RGTR VQFN RGT 16 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS54326RGTT VQFN RGT 16 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 7-Nov-2019 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) TPS54326PWPR HTSSOP PWP 14 2000 350.0 350.0 43.0 TPS54326RGTR VQFN RGT 16 3000 367.0 367.0 35.0 TPS54326RGTT VQFN RGT 16 250 210.0 185.0 35.0 PackMaterials-Page2

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PACKAGE OUTLINE RGT0016C VQFN - 1 mm max height SCALE 3.600 PLASTIC QUAD FLATPACK - NO LEAD A 3.1 B 2.9 PIN 1 INDEX AREA 3.1 2.9 1 MAX C SEATING PLANE 0.05 0.08 0.00 1.68 0.07 (0.2) TYP 5 8 EXPOSED THERMAL PAD 12X 0.5 4 9 4X SYMM 1.5 1 12 0.30 16X 0.18 16 13 0.1 C A B PIN 1 ID SYMM (OPTIONAL) 0.05 0.5 16X 0.3 4222419/B 11/2016 NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance. www.ti.com

EXAMPLE BOARD LAYOUT RGT0016C VQFN - 1 mm max height PLASTIC QUAD FLATPACK - NO LEAD ( 1.68) SYMM 16 13 16X (0.6) 1 12 16X (0.24) SYMM (2.8) (0.58) TYP 12X (0.5) 9 4 ( 0.2) TYP VIA 5 8 (R0.05) (0.58) TYP ALL PAD CORNERS (2.8) LAND PATTERN EXAMPLE SCALE:20X 0.07 MAX 0.07 MIN ALL AROUND ALL AROUND SOLDER MASK METAL OPENING SOLDER MASK METAL UNDER OPENING SOLDER MASK NON SOLDER MASK SOLDER MASK DEFINED DEFINED (PREFERRED) SOLDER MASK DETAILS 4222419/B 11/2016 NOTES: (continued) 4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature number SLUA271 (www.ti.com/lit/slua271). 5. Vias are optional depending on application, refer to device data sheet. If any vias are implemented, refer to their locations shown on this view. It is recommended that vias under paste be filled, plugged or tented. www.ti.com

EXAMPLE STENCIL DESIGN RGT0016C VQFN - 1 mm max height PLASTIC QUAD FLATPACK - NO LEAD ( 1.55) 16 13 16X (0.6) 1 12 16X (0.24) 17 SYMM (2.8) 12X (0.5) 9 4 METAL ALL AROUND 5 8 SYMM (R0.05) TYP (2.8) SOLDER PASTE EXAMPLE BASED ON 0.125 mm THICK STENCIL EXPOSED PAD 17: 85% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE SCALE:25X 4222419/B 11/2016 NOTES: (continued) 6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. www.ti.com

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