1、Conductive Polymer CathodeTantalumCapacitorsPrepare by : Andy # 2KEMET History# 3Global manufacturing # 4Tantalum ProcessPowder Press SinterFormation+ImpregnationConductive PolymerCounter electrodeC + Ag OvenAssembly Encapsulation Testing# 5Conductive Polymer Cathode Tantalum capacitor constructionA
2、nodeDielectric formationCathodePolymerTa2O5TantalumWireAnodeLead frameResin caseDielectricCathodeAnode# 6Tantalum capacitor constructionAnodeDielectric formationMnO2formationMnO2Ta2O5TaWireAnode Lead frameResin caseDielectricCathodeAnode# 7Polymer /MnO2/ Ta2O5/ TaSilver AdhesiveCarbonSilver PaintWas
3、herTantalum WireWeldLeadframe(- Cathode)Leadframe(+ Anode)Solid Tantalum Surface-Mount Capacitor# 8ESRESR spread of different capacitor technologyAluminum can capacitors10010-110-2Tantalum capacitors (MnO2)Polymer capacitors (PEDT)ESR value range ()# 9MnO2vs. Polymer100 1,000 10,000 100,000 1,000,00
4、0 10,000,000Frequency (Hz)0.010.1110100Impedance & ESR (Ohms)PolymerMnO2T495D 150 uF (MnO2) vs T520D 150 uF (Polymer)# 10150 F / 6 WVDCESR versus Frequency0.010.1110100 1,000 10,000 100,000 1,000,000 10,000,000Frequency (Hz)ESR(Ohms)T491V157M006Commercial MnO2T495V157M006“Low ESR” MnO2T520V157M006 P
5、olymer# 11Capacitance Roll-OffT495D 150 F (MnO2) vs. T520D 150 F (Polymer)101001,00010,000100,0001,000,00010,000,000100,000,000Frequency (Hz)050100150Capacitance (F)MnO2Polymer# 12Healing Effect of MnO2LayerCrackNickelTaTa2O5MnO2Mn2O3Electrical Conditioning (Aging)# 133.Oxygen feeds heated TaTaTa2O5
6、MnO22.MnO2conversion starts - O2generated - Ta2O5 to crystallineO21.Crack initiates current & heat4.Ta + O2RAPIDLY combine = Ignition“Ignition“# 14Evaporation of Conductive Polymer Layer CrackNickelTaPolymerTa2O5Polymer vacated(vaporized)Oxidation of Polymer Layer CrackNickelTaPolymerTa2O5Polymer ox
7、idizedPolymer Self-Healing Mechanism# 15MnO2vs. Polymer - IgnitionsMnO2MnO2MnO2MnO2MnO2Poly Poly Poly Poly PolyTest card with capacitors subjected to 2x Rated Voltage, appliedwith reverse polarity and 20 amperes current capability.# 16Median Values8210197%Ta-PolyKOVR106,310100% VRatedFR(PPM)1,70090%
8、 VRatedFR(PPM)45880% VRatedFR(PPM)950% VRatedFR(PPM)68%100 PPM FR% VRatedMnO2# 17Ripple capability High Performance Noise Absorption Decoupling of output voltage in DC-DC convertersPolymer capacitor47uF/6.3VVM= 27.5mVp-pTantalum capacitor47uF/6.3VVM= 54.4mVp-p# 18KEMET surge current testKEMETs exclu
9、sive 100% Surge Testing KEMET test simulates surge current in actual applications Conditions: RTotal450m, 1.1x Rated VoltageVerification level200uACurrent waveformIKEMET1.1VR/(0.45+ESR)Testing circuitProtection resistor 1kOhmPower supply unitReservoir capacitor 4700uFCurrent detector resistorFET swi
10、tch transistorCapacitor under test+RTOTAL# 19 Plug in capacitor to battery Battery voltage and internal battery resistance aredependent on battery chargeIBATT s.c.VB/(0.3 + ESR)ApplicationexampleLoadresistanceBatteryInternal batt.resistanceRISwitchRT=0.3ESRC+Capacitorunder testTesting circuitVB=4,2
11、VBattery surge# 20Stable parametersCapacitance dependent on DC bias voltage and temperaturemay degrade smoothing capability102030405060708090100110120012345670123456789101112Graph of capacitance stabilityCapacitance (uF)Temperature(C) DC bias voltage (V)Polymer capacitor T520A10uF/6.3V10203040506070
12、8090100110120012345670123456789101112Graph of capacitance stabilityDC bias voltage (V)Temperature(C)Capacitance (uF)Ceramic capacitor MLCC A10uF/6.3V# 21PIEZO EFFECTWhy Not Ceramics ? Output level - 1000Hz input sinus signal MLC capacitor 10uF/16V (Y5V)-300-200-1000100200300time (ms)Voltage (uV)Outp
13、ut level - 1000Hz input sinus signal Tantalum capacitor 10uF/10V-300-200-1000100200300time (ms)Voltage (uV)CERAMICPolymerBarium titanate used in ceramic capacitors is permitive material and exhibits PIEZO EFFECT = X5R,X7R,Y5V dielectrics can work as a small microphone or speaker and thus degrade sig
14、nal purity to create additional noiseCLEAR FILTERINGPolymer A10uF/6.3VCeramicA10uF/6.3VMechanical and/or Electrical StressOscilloscope G# 22Robustness against crackingHigh CV Ceramic Issues During Drop TestWhy Not Ceramics ? Reliability on High CVMechanical StressSensitivityPolymer capacitorCeramic
15、capacitor# 23Product optimization- Space Saving- Cost SavingMINIATURISATIONTantalum Polymer Capacitors10%-20% derating recommendation for polymer capacitorsRated voltage of polymer capacitor2.5V4.0V6.3VT520 seriesLine voltage1.8V3.3V5.0V35V Polymer TaHigh Voltage AOLow ESLFaceDown Polymer:Small Case
16、 I & MHigh Temp (150C/175C)CWR09, 19, 2915mOhm B Case# 24why Conductive Polymer Cathode Tantalum Capacitors ?More conductive cathode solution in compare to MnO2Performance of conductive polymer:T520 seriesLook to the future:CONDUCTIVE POLYMERLowerESRReduced ignitionLowprofile20%Derating# 25Polymer T
17、a-cap Component Performance Characteristics# 26Polymer Ta-cap Component Performance Characteristics# 27Polymer Ta-cap Component Performance Characteristics# 28Polymer Ta-cap Component Performance Characteristics# 29Polymer Ta-cap Component Performance Characteristics# 30Polymer Ta-cap Component Performance Characteristics
