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What happens when (47uF != 47uF)...

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Webinar showing engineers how the capacitance of different capacitors change. Your applications voltage, temperature, and frequency can cause shifts in the critical specification. Here's how to calculate your applications effect on polymer type capacitors.

Published in: Engineering
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What happens when (47uF != 47uF)...

  1. 1. if ( 47µF == 47µF) { true; } else {false;}
  2. 2. It's in what’s printed(on)? if ( 47µF == 47µF) { true; } else { False; }
  3. 3. one slide statement capacitance product group < 4.7µF MLCC application specific >220uF Polymer respective Tantalum
  4. 4. search.kemet.com
  5. 5. EIA-198-D • Testsetup and conditions for : 
 • Ceramic dielectric capacitors classes I, II, III
 • Polymer and Alu measured the same way C_min C_max Test Frequency V_rms V_DC 0,1pF 1nF 1kHz 1V 0V 1nF 10µF 1kHz 1V 0V 10µF 1800µF 120Hz 0,5V 0V
  6. 6. MLCC construction
  7. 7. VCC • VCC = voltage change capacitance • Proportional with electric field in the dielectric • thinner dielectric same voltage increase E-field
  8. 8. Net capacitance 47µF/6.3V
 compare case sizes 0805/ 1206/ 1210 0V 5V dC % 0805 42,3µF 11,3µF 26 % 1206 42,8µF 22,9µF 52 % 1210 48,3µF 29,4µF 69 %
  9. 9. dielectric physics • VCC = voltage change capacitance • Force applied on charged particles caused by an electrical field • thinner dielectric same voltage increase E-field
 ( Downsizing!)
  10. 10. Design improvements • Print Quantity Reduced ~30% prints • Chip Thickness Reduced ~ 0.42mm 1210 0805 Dieletric ~1,75µm ~1,40µm
  11. 11. Example 0805/10µF 6,3V Comparison between manufacturer A,B,C & D allvaluesareaverages Property UNIT A B C D Cap µF 11,1 10,8 9,3 9,1 DF % 7,3 8,0 4,6 4,6 UVBD V 65 96 144 114 IR @25°C MΩ 148 105 174 216 IR@125°C MΩ 112 13 46 94 Dielectric Thickness µm 1,38 1,55 1,74 1,78 Electrode Thickness µm 1,27 1,67 1,57 1,44 Active Layers [1] 395 323 371 333 Stress V/µm 66 98 146 115 K [1] 2690 3176 2817 3434 Grainsize µm 240 490 350 360
  12. 12. VCC 0805 47µF 6.3V
  13. 13. compare VCC measured versus simulated
  14. 14. precision of the VCC chart VCC K-SIM measured Cap_delta 1 0,2 % 2 % 1,8 % 5 -5,0 % -1 % 4,0 % 10 -20,0 % -20 % 0,0 % 16 -50,0 % -37 % 13,0 % 20 -60,0 % -52 % 8,0 % 25 -68,0 % -62 % 6,0 % 35 -77,0 % -75 % 2,0 % 50 -84,0 % -83 % 1,0 % 0 % 3,5 % 7 % 10,5 % 14 % 5 10 16 20 25 35 50
  15. 15. LTSpice capacitor simulation
  16. 16. C - Model in LT-SPICE • VCC is not yet included in this models
  17. 17. Compare MLCC / Polymer @120Hz, RT • AluPolymer in preparation for K-SIM MLCC 0805 MLCC 1210 Polymer B Cap/µF 11,8 29,1 47
  18. 18. Compare technologies 47µF/6V @5V AluPoly 1) TaPoly MLCC 0805 MLCC 1206 MLCC 1210 net Cap/µF 41 49 11,3 22,3 29,4 max Temp/°C 105 125 85 85 125 max Height
 /mm 9,7 2,1 1,45 1,8 2,8 Price2)/pcs
 @2000pcs
 0,3868 0,3984 0,2293 0,2475 0,4925 net c€/µF 0,9434 0,8131 2,0292 1,1099 1,6752 1) AluPoly Vr = 35V 2) price by Digikey for 2kpcs)
  19. 19. It's in what’s printed(on)? if ( 47µF == 47µF) { true = Polymer; AluPoly; } else { false = MLCC; Downsizing ++ ; netCap - - ; }
  20. 20. Thank You! Axel Schmidt Field application Engineer Cell +49 172 89 25 284 email: AxelSchmidt@kemet.com Hermann-Köhl-Str. 2 86899 Landsberg am Lech Germany www.kemet.com
  21. 21. VCC explanation • Nominal capacitance is measured 1kHz/0VDC/1VAC • Capacitance drop thru locked dipoles • Ripple current decrease • E-Field is voltage between electrode plates (distance) • Downsizing requires thinner dielectric • Thinner dielectric increase electrical field • capacitane loss is higher

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