TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 350-mW MONO AUDIO POWER AMPLIFIER WITH DIFFERENTIAL INPUTS • FullySpecifiedfor3.3-Vand5-VOperation D OR DGN PACKAGE • WidePowerSupplyCompatibility (TOP VIEW) 2.5V–5.5V • OutputPowerforRL=8W SHUTDOWN 1 8 VO- – 350mWatV =5V BYPASS 2 7 GND DD – 250mWatV =3.3V IN+ 3 6 VDD • UltralowSupplDyDCurrentinShutdown IN- 4 5 VO+ Mode...0.15µA • ThermalandShort-CircuitProtection • Surface-MountPackaging – SOIC – PowerPAD™MSOP DESCRIPTION The TPA321 is a bridge-tied load (BTL) audio power amplifier developed especially for low-voltage applications where internal speakers are required. Operating with a 3.3-V supply, the TPA321 can deliver 250 mW of continuous power into a BTL 8-W load at less than 1% THD+N throughout voice band frequencies. Although this device is characterized out to 20 kHz, its operation was optimized for narrower band applications such as cellular communications. The BTL configuration eliminates the need for external coupling capacitors on the output in most applications, which is particularly important for small battery-powered equipment. This device features a shutdown mode for power-sensitive applications with a quiescent current of 0.15 µA during shutdown. The TPA321isavailableinan8-pinSOICsurface-mount package and the surface-mount PowerPAD™ MSOP, which reducesboardspaceby50%andheightby40%. VDD 6 RF VDD Audio VDD/2 CS Input 1 m F RI 4 IN- - VO+ 5 CI 3 IN+ + 2 BYPASS CB 0.1 m F - VO- 8 350 mW + 7 GND 1 SHUTDOWN Bias From System Control Control Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexas Instrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet. PowerPADisatrademarkofTexasInstruments. PRODUCTIONDATAinformationiscurrentasofpublicationdate. Copyright©2000–2004,TexasInstrumentsIncorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarilyincludetestingofallparameters.

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedurescancausedamage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could causethedevicenottomeetitspublishedspecifications. AVAILABLEOPTIONS PACKAGEDDEVICES MSOP T A SMALLOUTLINE(1)(D) MSOP(1)(DGN) SYMBOLIZATION –40(cid:176)C to85(cid:176)C TPA321D TPA321DGN AJB (1) TheDandDGNpackagesareavailabletapedandreeled.Toorderatapedandreeledpart,addthe suffixRtothepartnumber(e.g.,TPA321DR). ABSOLUTE MAXIMUM RATINGS overoperatingfree-airtemperaturerange(unlessotherwisenoted)(1) UNIT V Supplyvoltage 6V DD V Inputvoltage –0.3VtoV +0.3V I DD Continuoustotalpowerdissipation Internallylimited(seeDissipationRatingTable) T Operatingfree-airtemperaturerange –40(cid:176)C to85(cid:176)C A T Operatingjunctiontemperaturerange –40(cid:176)C to150(cid:176)C J T Storagetemperaturerange –65(cid:176)C to150(cid:176)C stg Leadtemperature1,6mm(1/16inch)fromcasefor10seconds 260(cid:176)C (1) Stressesbeyondthoselistedunder"absolutemaximumratings"maycausepermanentdamagetothedevice.Thesearestressratings only,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunder"recommendedoperating conditions"isnotimplied.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability. DISSIPATION RATING TABLE PACKAGE T £ 25(cid:176)C DERATINGFACTOR T =70(cid:176)C T =85(cid:176)C A A A D 725mW 5.8mW/(cid:176)C 464mW 377mW DGN 2.14W(1) 17.1mW/(cid:176)C 1.37W 1.11W (1) SeetheTexasInstrumentsdocument,PowerPADThermallyEnhancedPackageApplicationReport (literaturenumberSLMA002),formoreinformationonthePowerPAD™package.Thethermaldata wasmeasuredonaPCBlayoutbasedontheinformationinthesectionentitledTexasInstruments RecommendedBoardforPowerPADonpage33ofthebeforementioneddocument. RECOMMENDED OPERATING CONDITIONS MIN MAX UNIT V Supplyvoltage 2.5 5.5 V DD V High-levelvoltage SHUTDOWN 0.9V V IH DD V Low-levelvoltage SHUTDOWN 0.1V V IL DD T Operatingfree-airtemperature –40 85 (cid:176)C A 2

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 ELECTRICAL CHARACTERISTICS atspecifiedfree-airtemperature,V =3.3V,T =25(cid:176)C (unlessotherwisenoted) DD A PARAMETER TESTCONDITIONS MIN TYP MAX UNIT |V | Outputoffsetvoltage(measureddifferentially) SHUTDOWN=0V,R =8W, R =10kW 5 20 mV OO L F PSRR Powersupplyrejectionratio V =3.2Vto3.4V 85 dB DD I Supplycurrent(seeFigure3) SHUTDOWN=0V,R =10kW 0.7 1.5 mA DD F I Supplycurrent,shutdownmode(seeFigure4) SHUTDOWN=V ,R =10kW 0.15 5 µA DD(SD) DD F |I | High-levelinputcurrent SHUTDOWN,V =3.3V,V =3.3V 1 µA IH DD I |I | Low-levelinputcurrent SHUTDOWN,V =3.3V,V =0V 1 µA IL DD I OPERATING CHARACTERISTICS V =3.3V,T =25(cid:176)C, R =8W DD A L PARAMETER TESTCONDITIONS MIN TYP MAX UNIT P Outputpower(1) THD=0.5%, SeeFigure9 250 mW O P =250mW, f=20Hzto4kHz, THD+N Totalharmonicdistortionplusnoise O 1.3% A =-2V/V, SeeFigure7 V Maximumoutputpowerbandwidth A =-2V/V,THD=3%,SeeFigure7 10 kHz V B Unity-gainbandwidth Openloop, SeeFigure15 1.4 MHz 1 Supplyripplerejectionratio f=1kHz,C =1µF,SeeFigure2 71 dB B A =–1V/V, C =0.1µF, Vn Noiseoutputvoltage RV=32W , SeBeFigure19 15 µV(rms) L (1) Outputpowerismeasuredattheoutputterminalsofthedeviceatf=1kHz. ELECTRICAL CHARACTERISTICS atspecifiedfree-airtemperature,V =5V,T =25(cid:176)C (unlessotherwisenoted) DD A PARAMETER TESTCONDITIONS MIN TYP MAX UNIT |V | Outputoffsetvoltage(measureddifferentially) SHUTDOWN=0V,R =8W, R =10kW 5 20 mV OO L F PSRR Powersupplyrejectionratio V =4.9Vto5.1V 78 dB DD I Supplycurrent(seeFigure3) SHUTDOWN=0V,R =10kW 0.7 1.5 mA DD F I Supplycurrent,shutdownmode(seeFigure4) SHUTDOWN=V ,R =10kW 0.15 5 µA DD(SD) DD F |I | High-levelinputcurrent SHUTDOWN,V =5.5V,V =V 1 µA IH DD I DD |I | Low-levelinputcurrent SHUTDOWN,V =5.5V,V =0V 1 µA IL DD I OPERATING CHARACTERISTICS V =5V,T =25(cid:176)C, R =8W DD A L PARAMETER TESTCONDITIONS MIN TYP MAX UNIT P Outputpower THD=0.5%, SeeFigure13 700 mW O P =350mW, f=20Hzto4kHz,See THD+N Totalharmonicdistortionplusnoise O 1% A =–2V/V, Figure11 V Maximumoutputpowerbandwidth A =–2V/V,THD=2%,SeeFigure11 10 kHz V B Unity-gainbandwidth Openloop, SeeFigure16 1.4 MHz 1 Supplyripplerejectionratio f=1kHz,C =1µF,SeeFigure2 65 dB B A =-1V/V, C =0.1µF, Vn Noiseoutputvoltage RV=32W , SeBeFigure20 15 µV(rms) L 3

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 TerminalFunctions TERMINAL I/O DESCRIPTION NAME NO. BYPASSisthetaptothevoltagedividerforinternalmid-supplybias.Thisterminalshouldbeconnected BYPASS 2 I toa0.1-µFto1-µFcapacitorwhenusedasanaudioamplifier. GND 7 GNDisthegroundconnection. IN- 4 I IN-istheinvertinginput.IN-istypicallyusedastheaudioinputterminal. IN+ 3 I IN+isthenoninvertinginput.IN+istypicallytiedtotheBYPASSterminalforSEoperations. SHUTDOWN 1 I SHUTDOWNplacestheentiredeviceinshutdownmodewhenheldhigh(I ~0.15µA). DD V 6 V isthesupplyvoltageterminal. DD DD V + 5 O V +isthepositiveBTLoutput. O O V - 8 O V -isthenegativeBTLoutput. O O PARAMETER MEASUREMENT INFORMATION VDD 6 Audio RF VDD/2 CS VDD Input 1 m F RI 4 IN- - VO+ 5 CI 3 IN+ + 2 BYPASS RL = 8 W CB 0.1 m F - VO- 8 + 7 GND 1 SHUTDOWN Bias Control Figure1.TestCircuit 4

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 TYPICAL CHARACTERISTICS TableofGraphs FIGURE k Supplyvoltagerejectionratio vsFrequency 2 SVR I Supplycurrent vsSupplyvoltage 3,4 DD vsSupplyvoltage 5 P Outputpower O vsLoadresistance 6 vsFrequency 7,8,11,12 THD+N Totalharmonicdistortionplusnoise vsOutputpower 9,10,13,14 Open-loopgainandphase vsFrequency 15,16 Closed-loopgainandphase vsFrequency 17,18 V Outputnoisevoltage vsFrequency 19,20 n P Powerdissipation vsOutputpower 21,22 D SUPPLYVOLTAGEREJECTIONRATIO SUPPLYCURRENT vs vs FREQUENCY SUPPLYVOLTAGE 0 1.1 RL = 8 W SHUTDOWN = 0 V dB −10 CB = 1 m F RF = 10 kW − 0.9 o −20 Rati mA n −30 − Rejectio −40 Current 0.7 ge −50 ply 0.5 a p olt −60 VDD = 5 V Su pply V −70 − DD 0.3 Su VDD = 3.3 V I − −80 R 0.1 SV −90 k −100 −0.1 20 100 1 k 10 k 20 k 2 3 4 5 6 f − Frequency − Hz VDD − Supply Voltage − V Figure2. Figure3. 5

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 SUPPLYCURRENT(SHUTDOWN) vs SUPPLYVOLTAGE 0.5 SHUTDOWN = VDD 0.45 RF = 10 kW A 0.4 m− nt 0.35 e urr C 0.3 y pl p 0.25 u S − D) 0.2 S D( D 0.15 I 0.1 0.05 2 2.5 3 3.5 4 4.5 5 5.5 VDD − Supply Voltage − V Figure4. OUTPUTPOWER vs SUPPLYVOLTAGE 1000 THD+N 1% 800 W m − er 600 w Po RL = 8 W ut p ut 400 O − RL = 32 W O P 200 0 2 2.5 3 3.5 4 4.5 5 5.5 VDD − Supply Voltage − V Figure5. 6

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 OUTPUTPOWER vs LOADRESISTANCE 800 THD+N = 1% 700 W 600 − m VDD = 5 V er 500 w o P ut 400 p ut − O 300 VDD = 3.3 V O P 200 100 0 8 16 24 32 40 48 56 64 RL − Load Resistance − W Figure6. TOTALHARMONICDISTORTION+NOISE TOTALHARMONICDISTORTION+NOISE vs vs FREQUENCY FREQUENCY 10 10 % VDD = 3.3 V % VDD = 3.3 V Noise − PROL == 82 5W0 mW AV = −20 V/V Noise − RAVL == −8 2W V/V PO = 50 mW + + n n o 1 o 1 orti orti st st Di Di nic AV =− 10 V/V nic mo AV = −2 V/V mo PO = 125 mW ar ar H 0.1 H 0.1 al al ot ot T T − − N N + + D D H H T T PO = 250 mW 0.01 0.01 20 100 1k 10k 20k 20 100 1k 10k 20k f − Frequency − Hz f − Frequency − Hz Figure7. Figure8. 7

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 TOTALHARMONICDISTORTION+NOISE TOTALHARMONICDISTORTION+NOISE vs vs OUTPUTPOWER OUTPUTPOWER 10 10 − % VDD = 3.3 V − % f = 20 kHz e f = 1 kHz e ois AV = −2 V/V ois N N f = 10 kHz + + n n o 1 o 1 orti orti st st f = 1 kHz Di Di c c oni RL = 8 W oni m m ar ar H 0.1 H 0.1 al al ot ot f = 20 Hz −T −T VDD = 3.3 V +N +N RL = 8 W HD HD AV = −2 V/V T T 0.01 0.01 0.04 0.1 0.16 0.22 0.28 0.34 0.4 0.01 0.1 1 PO − Output Power − W PO − Output Power − W Figure9. Figure10. TOTALHARMONICDISTORTION+NOISE TOTALHARMONICDISTORTION+NOISE vs vs FREQUENCY FREQUENCY 10 10 % VDD = 5 V % VDD = 5 V oise − PROL == 83 5W0 mW AV = −20 V/V oise − RAVL == −8 2W V/V N N PO = 50 mW + + n n o 1 o 1 orti orti st st Di Di c c ni AV =− 10 V/V ni mo mo PO = 175 mW ar AV = −2 V/V ar H 0.1 H 0.1 al al ot ot T T − − N N + + HD HD PO = 350 mW T T 0.01 0.01 20 100 1k 10k 20k 20 100 1k 10k 20k f − Frequency − Hz f − Frequency − Hz Figure11. Figure12. 8

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 TOTALHARMONICDISTORTION+NOISE TOTALHARMONICDISTORTION+NOISE vs vs OUTPUTPOWER OUTPUTPOWER 10 10 − % VDD = 5 V − % f = 20 kHz e f = 1 kHz e ois AV = −2 V/V ois N N + + f = 10 kHz n n o 1 o 1 orti orti st RL = 8 W st f = 1 kHz Di Di c c ni ni o o m m ar ar H 0.1 H 0.1 f = 20 Hz al al ot ot −T −T VDD = 5 V +N +N RL = 8 W HD HD AV = −2 V/V T T 0.01 0.01 0.1 0.25 0.40 0.55 0.70 0.85 1 0.01 0.1 1 PO − Output Power − W PO − Output Power − W Figure13. Figure14. OPEN-LOOPGAINANDPHASE vs FREQUENCY 40 180 Phase VDD = 3.3 V RL = Open 30 Gain 120 B 20 − d 60 n p Gai 10 0 °se − o a Lo 0 Ph n- e p −60 O −10 −120 −20 −30 −180 1 101 102 103 104 f − Frequency − kHz Figure15. 9

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 OPEN-LOOPGAINANDPHASE vs FREQUENCY 40 180 Phase VDD = 5 V RL = Open 30 Gain 120 B 20 − d 60 n p Gai 10 0 °se − o a Lo 0 Ph n- e p −60 O −10 −120 −20 −30 −180 1 101 102 103 104 f − Frequency − kHz Figure16. CLOSED-LOOPGAINANDPHASE vs FREQUENCY 1 180 Phase 0.75 0.5 170 0.25 B d − 0 160 Gain −0.25 Gain ° oop −0.5 150 ase − L h d- −0.75 P e s o −1 140 Cl VDD = 3.3 V −1.25 RL = 8 W −1.5 PO = 0.25 W 130 CI =1 m F −1.75 −2 120 101 102 103 104 105 106 f − Frequency − Hz Figure17. 10

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 CLOSED-LOOPGAINANDPHASE vs FREQUENCY 1 180 Phase 0.75 0.5 170 0.25 B d − 0 160 n Gain Gai −0.25 ° oop −0.5 150 ase − L h d- −0.75 P e s o −1 140 Cl VDD = 5 V −1.25 RL = 8 W −1.5 PO = 0.35 W 130 CI =1 m F −1.75 −2 120 101 102 103 104 105 106 f − Frequency − Hz Figure18. OUTPUTNOISEVOLTAGE OUTPUTNOISEVOLTAGE vs vs FREQUENCY FREQUENCY 100 100 VDD = 3.3 V VDD = 5 V BW = 22 Hz to 22 kHz BW = 22 Hz to 22 kHz ms) RL = 32 W s) RL = 32 W V(r CB =0.1 m F rm CB =0.1 m F m− AV = −1 V/V V( AV = −1 V/V e m− e Voltag VO BTL Voltage VO BTL ois 10 se 10 utput N VO+ put Noi VO+ O ut − O n − V n V 1 1 20 100 1 k 10 k 20 k 20 100 1 k 10 k 20 k f − Frequency − Hz f − Frequency − Hz Figure19. Figure20. 11

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 POWERDISSIPATION POWERDISSIPATION vs vs OUTPUTPOWER OUTPUTPOWER 300 720 270 640 W W m 240 m 560 − − n n o o ati 210 ati 480 p p si si s s Di Di er 180 er 400 w w o o P P − 150 − 320 D D P P VDD = 3.3 V VDD = 5 V 120 RL = 8 W 240 RL = 8 W 90 160 0 100 200 300 400 0 200 400 600 800 1000 1200 PO − Output Power − mW PO − Output Power − mW Figure21. Figure22. 12

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 APPLICATION INFORMATION BRIDGE-TIED LOAD Figure 23 shows a linear audio power amplifier (APA) in a BTL configuration. The TPA321 BTL amplifier consists of two linear amplifiers driving both ends of the load. There are several potential benefits to this differential drive configurationbut power to the load should be initially considered. The differential drive to the speaker means that as one side is slewing up, the other side is slewing down, and vice versa. This, in effect, doubles the voltage swing on the load as compared to a ground-referenced load. Plugging 2 · V into the power equation, where O(PP) voltageissquared,yields4· theoutputpowerfromthesamesupplyrailandloadimpedance(seeEquation1). V O(PP) V(RMS) (cid:1) 2(cid:2)2 2 V (RMS) Power (cid:1) R L (1) VDD VO(PP) RL 2x VO(PP) VDD -VO(PP) Figure23.Bridge-TiedLoadConfiguration Inatypicalportablehandheldequipmentsoundchanneloperatingat 3.3 V, bridging raises the power into an 8-W speaker from a single-ended (SE, ground reference) limit of 62.5 mW to 250 mW. In sound power that is a 6-dB improvement, which is loudness that can be heard. In addition to increased power, there are frequency response concerns. Consider the single-supply SE configuration shown in Figure 24. A coupling capacitor is required to block the dc offset voltage from reaching the load. These capacitors can be quite large (approximately 33 µF to 1000 µF) so they tend to be expensive, heavy, occupy valuable PCB area, and have the additional drawback of limiting low-frequency performance of the system. This frequency limiting effect is due to the high pass filter networkcreatedwiththespeakerimpedanceandthecouplingcapacitanceandiscalculatedwithEquation2. f (cid:1) 1 c 2(cid:1)R C L C (2) For example, a 68-µF capacitor with an 8-W speaker would attenuate low frequencies below 293 Hz. The BTL configurationcancelsthedcoffsets, eliminating the need for the blocking capacitors. Low-frequency performance is then limited only by the input network and speaker response. Cost and PCB space are also minimized by eliminatingthebulkycouplingcapacitor. 13

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 APPLICATION INFORMATION (continued) VDD -3 dB VO(PP) CC RL VO(PP) fc Figure24.Single-EndedConfigurationandFrequencyResponse Increasing power to the load does carry a penalty of increased internal power dissipation. The increased dissipation is understandable considering that the BTL configuration produces 4· the output power of a SE configuration.Internaldissipationversusoutputpowerisdiscussedfurtherinthethermalconsiderationssection. BTL AMPLIFIER EFFICIENCY Linear amplifiers are inefficient. The primary cause of these inefficiencies is voltage drop across the output stage transistors. There are two components of the internal voltage drop. One is the headroom or dc voltage drop that varies inversely to output power. The second component is due to the sine-wave nature of the output. The total voltage drop can be calculated by subtracting the RMS value of the output voltage from V . The internal voltage DD drop multiplied by the RMS value of the supply current, I , determines the internal power dissipation of the DD(RMS) amplifier. An easy-to-use equation to calculate efficiency starts out as being equal to the ratio of power from the power supplytothe power delivered to the load. To accurately calculate the RMS values of power in the load and in the amplifier,thecurrentandvoltagewaveformshapesmustfirstbeunderstood(seeFigure25). VO IDD VL(RMS) IDD(RMS) Figure25.VoltageandCurrentWaveformsforBTLAmplifiers Although the voltages and currents for SE and BTL are sinusoidal in the load, currents from the supply are different between SE and BTL configurations. In an SE application the current waveform is a half-wave rectified shape, whereas in BTL it is a full-wave rectified waveform. This means RMS conversion factors are different. Keep in mind that for most of the waveform both the push and pull transistors are not on at the same time, which supports the fact that each amplifier in the BTL device only draws current from the supply for half the waveform. Thefollowingequationsarethebasisforcalculatingamplifierefficiency. 14

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 APPLICATION INFORMATION (continued) P L Efficiency (cid:1) P SUP where 2 V 2 L(cid:2)RMS(cid:3) Vp PL (cid:1) R (cid:1) 2R L L V P V (cid:1) L(cid:2)RMS(cid:3) (cid:4)2 V 2V DD P PSUP (cid:1) VDDIDD(cid:2)RMS(cid:3) (cid:1) (cid:1)R L 2V P IDD(cid:2)RMS(cid:3)(cid:1) (cid:1)R L (3) 1(cid:2)2 (cid:1)(cid:3)PLRL(cid:4) (cid:1)V 2 P EfficiencyofaBTLconfiguration(cid:1) (cid:1) 2V 2V DD DD (4) Table 1 employs Equation 4 to calculate efficiencies for three different output power levels. The efficiency of the amplifier is quite low for lower power levels and rises sharply as power to the load is increased resulting in a nearlyflatinternalpowerdissipationoverthenormaloperating range. The internal dissipation at full output power is less than in the half-power range. Calculating the efficiency for a specific system is the key to proper power supplydesign. Table1.EfficiencyvsOutputPowerin3.3-V8-W BTLSystems PEAK-to-PEAK INTERNAL OUTPUTPOWER EFFICIENCY VOLTAGE DISSIPATION (W) (%) (V) (W) 0.125 33.6 1.41 0.26 0.25 47.6 2.00 0.29 0.375 58.3 2.45(1) 0.28 (1) High-peakvoltagevaluescausetheTHDtoincrease. A final point to remember about linear amplifiers (either SE or BTL) is how to manipulate the terms in the efficiency equation to utmost advantage when possible. Note that in Equation 4, V is in the denominator. This DD indicatesthatasV goesdown,efficiencygoesup. DD 15

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 APPLICATION SCHEMATICS Figure26isaschematicdiagramofatypicalhandheldaudioapplicationcircuit,configuredforagainof–10V/V. 5 CpFF R50F kW VDD 6 VDD Audio VDD/2 CS Input 1 m F 4 IN- - VO+ 5 0.4C7I m F 10R kIW 3 IN+ + 2 BYPASS CB 2.2 m F - VO- 8 350 mW + 7 GND 1 SHUTDOWN Bias From System Control Control Figure26.TPA321ApplicationCircuit Figure 27 is a schematic diagram of a typical handheld audio application circuit, configured for a gain of –10 V/V withadifferentialinput. 50R kFW VDD 6 VDD Audio VDD/2 CS Input- RI 1 m F 10 kW 4 IN- - VO+ 5 CI 3 IN+ + RI RF Audio 10 kW 50 kW Input+ 2 BYPASS CI 2.2C m BF - VO- 8 700 mW + 7 GND 1 SHUTDOWN Bias From System Control Control Figure27.TPA321ApplicationCircuitWithDifferentialInput It is important to note that using the additional R resistor connected between IN+ and BYPASS causes V /2 to F DD shift slightly, which could influence the THD+N performance of the amplifier. Although an additional external operational amplifier could be used to buffer BYPASS from R , tests in the lab have shown that the THD+N F performance is only minimally affected by operating in the fully differential mode as shown in Figure 27. The followingsectionsdiscusstheselectionofthecomponentsusedinFigure26andFigure27. 16

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 COMPONENT SELECTION GainSettingResistors,R andR F I ThegainforeachaudioinputoftheTPA321issetbyresistorsR andR accordingtoEquation5forBTLmode. F I (cid:3)R (cid:4) F BTLGain (cid:2)AV (cid:2)(cid:1)2 R I (5) BTL mode operation brings about the factor 2 in the gain equation due to the inverting amplifier mirroring the voltage swing across the load. Given that the TPA321 is a MOS amplifier, the input impedance is high; consequently, input leakage currents are not generally a concern, although noise in the circuit increases as the value of R increases. In addition, a certain range of R values is required for proper start-up operation of the F F amplifier. Taken together, it is recommended that the effective impedance seen by the inverting node of the amplifierbesetbetween5kW and20kW. TheeffectiveimpedanceiscalculatedinEquation6. R R EffectiveImpedance (cid:2) F I R (cid:1)R F I (6) As an example, consider an input resistance of 10 kW and a feedback resistor of 50 kW. The BTL gain of the amplifier would be –10 V/V, and the effective impedance at the inverting terminal would be 8.3 kW, which is well withintherecommendedrange. For high-performance applications metal film resistors are recommended because they tend to have lower noise levels than carbon resistors. For values of R above 50 kW, the amplifier tends to become unstable due to a pole F formed from R and the inherent input capacitance of the MOS input structure. For this reason, place a small F compensation capacitor (C ) of approximately 5 pF in parallel with R when R is greater than 50 kW. In effect, F F F thiscreatesalow-passfilternetworkwiththecutofffrequencydefinedinEquation7. −3 dB f (cid:1) 1 c 2(cid:1)R C F F fc (7) Forexample,ifR is100kW andC is5pFthenf is318kHz,whichiswelloutsideofaudiorange. F F c InputCapacitor,C I In the typical application, input capacitor C is required to allow the amplifier to bias the input signal to the proper I dc level for optimum operation. In this case, C and R form a high-pass filter with the corner frequency I I determinedinEquation8. 17

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 −3 dB f (cid:1) 1 c 2(cid:1)R C I I fc (8) The value of C is important to consider as it directly affects the bass (low-frequency) performance of the circuit. I Consider the example where R is 10 kW and the specification calls for a flat bass response down to 40 Hz. I Equation8isreconfiguredasEquation9. C (cid:1) 1 I 2(cid:1)R f I c (9) In this example, C is 0.40 µF, so one would likely choose a value in the range of 0.47 µF to 1 µF. A further I consideration for this capacitor is the leakage path from the input source through the input network (R, C) and I I thefeedbackresistor(R )totheload.Thisleakagecurrentcreatesadcoffsetvoltageattheinputtotheamplifier F that reduces useful headroom, especially in high gain applications. For this reason a low-leakage tantalum or ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in most applications, as the dc level there is held at V /2, which is likely higher DD thanthesourcedclevel.Itisimportanttoconfirmthecapacitorpolarityintheapplication. PowerSupplyDecoupling,C S The TPA321 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic distortion (THD) is as low as possible. Power supply decoupling also prevents oscillations for long lead lengths between the amplifier and the speaker. The optimum decoupling is achieved by using two capacitors of different types that target different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor, typically 0.1 µF, placed as close as possible to the device V lead, works best. For filtering DD lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 µF or greater placed near the audio poweramplifierisrecommended. MidrailBypassCapacitor,C B The midrail bypass capacitor, C , is the most critical capacitor and serves several important functions. During B start-up or recovery from shutdown mode, C determines the rate at which the amplifier starts up. The second B function is to reduce noise produced by the power supply caused by coupling into the output drive signal. This noiseisfromthemidrailgenerationcircuit internal to the amplifier, which appears as degraded PSRR and THD + N. The capacitor is fed from a 250-kW source inside the amplifier. To keep the start-up pop as low as possible, the relationship shown in Equation 10 should be maintained, which insures the input capacitor is fully charged beforethebypasscapacitorisfullychargedandtheamplifierstartsup. 10 1 (cid:3) (cid:4)CB(cid:1)250kW (cid:5) (cid:4)RF(cid:2)RI(cid:5)CI (10) As an example, consider a circuit where C is 2.2 µF, C is 0.47 µF, R is 50 kW, and R is 10 kW. Inserting these B I F I valuesintotheEquation10weget: 18.2£ 35.5 which satisfies the rule. Bypass capacitor, C , values of 2.2-µF to 1-µF ceramic or tantalum low-ESR capacitors B arerecommendedforthebestTHDandnoiseperformance. 18

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 USING LOW-ESR CAPACITORS Low-ESR capacitors are recommended throughout this application. A real (as opposed to ideal) capacitor can be modeledsimplyasaresistorinserieswithanideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance, the more the realcapacitorbehaveslikeanidealcapacitor. 5-V VERSUS 3.3-V OPERATION The TPA321 operates over a supply range of 2.5 V to 5.5 V. This data sheet provides full specifications for 5-V and 3.3-V operation, as these are considered to be the two most common standard voltages. There are no special considerations for 3.3-V versus 5-V operation with respect to supply bypassing, gain setting, or stability. The most important consideration is that of output power. Each amplifier in TPA321 can produce a maximum voltage swing of V –1 V. This means, for 3.3-V operation, clipping starts to occur when V = 2.3 V as DD O(PP) opposedtoV =4 V at 5 V. The reduced voltage swing subsequently reduces maximum output power into an O(PP) 8-W loadbeforedistortionbecomessignificant. Operation from 3.3-V supplies, as can be shown from the efficiency formula in Equation 4, consumes approximatelytwo-thirdsthesupplypowerforagivenoutput-powerlevelthanoperationfrom5-Vsupplies. HEADROOM AND THERMAL CONSIDERATIONS Linear power amplifiers dissipate a significant amount of heat in the package under normal operating conditions. A typical music CD requires 12 dB to 15 dB of dynamic headroom to pass the loudest portions without distortion as compared with the average power output. The TPA321 data sheet shows that when the TPA321 is operating froma5-Vsupplyintoa8-W speaker,350mWpeaksareavailable.ConvertingwattstodB: P P (cid:1) 10Log W (cid:1)10Log 350mW (cid:1)–4.6dB dB P 1W ref Subtractingtheheadroomrestrictiontoobtaintheaveragelisteninglevelwithoutdistortionyields: 4.6dB –15dB=–19.6dB(15-dBheadroom) 4.6dB –12dB=–16.6dB(12-dBheadroom) 4.6dB –9dB=–13.6dB(9-dBheadroom) 4.6dB –6dB=–10.6dB(6-dBheadroom) 4.6dB –3dB=–7.6dB(3-dBheadroom) ConvertingdBbackintowatts: P =10PdB/10· P W ref =11mW(15dBheadroom) =22mW(12-dBheadroom) =44mW(9-dBheadroom) =88mW(6-dBheadroom) =175mW(3-dBheadroom) This is valuable information to consider when attempting to estimate the heat dissipation requirements for the amplifier system. Comparing the absolute worst case, which is 350 mW of continuous power output with 0 dB of headroom, against 12-dB and 15-dB applications drastically affects maximum ambient temperature ratings for the system. Using the power dissipation curves for a 5-V, 8-W system, the internal dissipation in the TPA321 and maximumambienttemperaturesisshowninTable2. 19

TPA321 www.ti.com SLOS312C–JUNE2000–REVISEDJUNE2004 Table2.TPA321PowerRating,5-V,8-W BTL PEAKOUTPUT MAXIMUMAMBIENT POWER AVERAGEOUTPUT POWERDISSIPATION TEMPERATURE POWER (mW) (mW) 0CFM 350 350mW 600 46(cid:176)C 350 175mW(3dB) 500 64(cid:176)C 350 88mW(6dB) 380 85(cid:176)C 350 44mW(9dB) 300 98(cid:176)C 350 22mW(12dB) 200 115(cid:176)C 350 11mW(15dB) 180 119(cid:176)C Table 2 shows that the TPA321 can be used to its full 350-mW rating without any heat sinking in still air up to 46(cid:176)C. 20

PACKAGE OPTION ADDENDUM www.ti.com 24-Aug-2018 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) TPA321D ACTIVE SOIC D 8 75 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 TPA321 & no Sb/Br) TPA321DGN ACTIVE MSOP- DGN 8 80 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 AJB PowerPAD & no Sb/Br) TPA321DGNR ACTIVE MSOP- DGN 8 2500 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 AJB PowerPAD & no Sb/Br) TPA321DR ACTIVE SOIC D 8 2500 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 TPA321 & 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 24-Aug-2018 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 26-Feb-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) TPA321DGNR MSOP- DGN 8 2500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 Power PAD TPA321DR SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 26-Feb-2019 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) TPA321DGNR MSOP-PowerPAD DGN 8 2500 358.0 335.0 35.0 TPA321DR SOIC D 8 2500 350.0 350.0 43.0 PackMaterials-Page2

PACKAGE OUTLINE D0008A SOIC - 1.75 mm max height SCALE 2.800 SMALL OUTLINE INTEGRATED CIRCUIT C SEATING PLANE .228-.244 TYP [5.80-6.19] .004 [0.1] C A PIN 1 ID AREA 6X .050 [1.27] 8 1 2X .189-.197 [4.81-5.00] .150 NOTE 3 [3.81] 4X (0 -15 ) 4 5 8X .012-.020 B .150-.157 [0.31-0.51] .069 MAX [3.81-3.98] .010 [0.25] C A B [1.75] NOTE 4 .005-.010 TYP [0.13-0.25] 4X (0 -15 ) SEE DETAIL A .010 [0.25] .004-.010 0 - 8 [0.11-0.25] .016-.050 [0.41-1.27] DETAIL A (.041) TYPICAL [1.04] 4214825/C 02/2019 NOTES: 1. Linear dimensions are in inches [millimeters]. Dimensions in parenthesis are for reference only. Controlling dimensions are in inches. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed .006 [0.15] per side. 4. This dimension does not include interlead flash. 5. Reference JEDEC registration MS-012, variation AA. www.ti.com

EXAMPLE BOARD LAYOUT D0008A SOIC - 1.75 mm max height SMALL OUTLINE INTEGRATED CIRCUIT 8X (.061 ) [1.55] SYMM SEE DETAILS 1 8 8X (.024) [0.6] SYMM (R.002 ) TYP [0.05] 5 4 6X (.050 ) [1.27] (.213) [5.4] LAND PATTERN EXAMPLE EXPOSED METAL SHOWN SCALE:8X SOLDER MASK SOLDER MASK METAL OPENING OPENING METAL UNDER SOLDER MASK EXPOSED METAL EXPOSED METAL .0028 MAX .0028 MIN [0.07] [0.07] ALL AROUND ALL AROUND NON SOLDER MASK SOLDER MASK DEFINED DEFINED SOLDER MASK DETAILS 4214825/C 02/2019 NOTES: (continued) 6. Publication IPC-7351 may have alternate designs. 7. Solder mask tolerances between and around signal pads can vary based on board fabrication site. www.ti.com

EXAMPLE STENCIL DESIGN D0008A SOIC - 1.75 mm max height SMALL OUTLINE INTEGRATED CIRCUIT 8X (.061 ) [1.55] SYMM 1 8 8X (.024) [0.6] SYMM (R.002 ) TYP [0.05] 5 4 6X (.050 ) [1.27] (.213) [5.4] SOLDER PASTE EXAMPLE BASED ON .005 INCH [0.125 MM] THICK STENCIL SCALE:8X 4214825/C 02/2019 NOTES: (continued) 8. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 9. Board assembly site may have different recommendations for stencil design. www.ti.com

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