Low inductance electroytic capacitor
A capacitor that is capable of exhibiting good electrical properties under a wide variety of different conditions is provided. The capacitor contains a capacitor element that includes a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric and includes a conductive polymer. The capacitor also contains multiple exposed anode lead portions that are electrically connected to respective anode terminations and a planar cathode termination that is electrically connected to the solid electrolyte.
1. A solid electrolytic capacitor comprising:
a capacitor element comprising a sintered anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric, wherein the solid electrolyte includes a conductive polymer, wherein the capacitor element defines opposing first and second ends and opposing upper and lower surfaces;
a first exposed anode lead portion extending from the first end of the capacitor element;
a first anode termination that is electrically connected to the first exposed anode lead portion;
a second exposed anode lead portion extending from the second end of the capacitor element;
a second anode termination that is spaced apart from the first anode termination and electrically connected to the second exposed anode lead portion; and
a planar cathode termination that is positioned adjacent to the lower surface of the capacitor element and electrically connected to the solid electrolyte;
wherein a continuous anode lead extends through the first end and the second end of the capacitor element, thereby defining the first exposed anode lead portion and the second exposed anode lead portion, wherein a distance between the first exposed anode lead portion and the second exposed anode lead portion to the lower surface of the of the capacitor element ranges from about 0.1 millimeter to about 1 millimeter.
2. The solid electrolytic capacitor of claim 1 , wherein the first anode termination, the second anode termination, or both include a planar portion that is generally parallel with a lower surface of the capacitor element.
3. The solid electrolytic capacitor of claim 1 , wherein the first anode termination, the second anode termination, or both include a planar portion that is substantially in the same plane as the cathode termination.
4. The solid electrolytic capacitor of claim 1 , wherein the cathode termination is generally parallel with a lower surface of the capacitor element.
5. The solid electrolytic capacitor of claim 1 , wherein the anode body includes tantalum and the dielectric includes tantalum pentoxide.
6. The solid electrolytic capacitor of claim 1 , wherein the solid electrolyte contains at least one layer formed from a dispersion of conductive polymer particles.
7. The solid electrolytic capacitor of claim 1 , wherein the conductive polymer includes poly(3,4-ethylenedioxythiophene), or a derivative thereof.
8. The solid electrolytic capacitor of claim 1 , wherein the anode body is formed from a valve metal powder having a specific charge of from about 5,000 to about 100,000 μF*V/g.
9. The solid electrolytic capacitor of claim 1 , wherein the anode body is formed from a valve metal powder having a specific charge of from about 100,000 to about 600,000 μF*V/g.
10. The solid electrolytic capacitor of claim 1 , further comprising a housing that encloses the capacitor element and leaves exposed at least a lower surface of the cathode termination.
11. The solid electrolytic capacitor of claim 10 , wherein the housing leaves exposed at least a lower surface of the first anode termination, the second anode termination, or both.
12. The solid electrolytic capacitor of claim 11 , where the exposed lower surface of the cathode termination is generally in the same plane as the exposed lower surface of the first anode termination, the second anode termination, or both.
13. The solid electrolytic capacitor of claim 1 , wherein the capacitor exhibits an impedance of about 1 ohm or less over a frequency range of from about 1 kHz to about 100 MHz.
14. The solid electrolytic capacitor of claim 1 , wherein the solid electrolytic capacitor exhibits about 40 dB or more of attenuation (S 21 parameter) over a frequency range of from about 0.1 MHz to about 500 MHz.
15. The solid electrolytic capacitor of claim 1 , wherein the solid electrolytic capacitor exhibits about 20 dB or more of attenuation (S 21 parameter) over a frequency range of from about 500 MHz to about 10 GHz.
16. The solid electrolytic capacitor of claim 1 , wherein the capacitor exhibits an ESR of about 800 mohms or less, as determined at an operating frequency of 100 kHz and temperature of 23° C.
17. The solid electrolytic capacitor of claim 1 , wherein the capacitor element has a height, and the distance between the first exposed anode lead portion and the second exposed anode lead portion to the lower surface of the of the capacitor element is about 0.1 to about 0.5 times the height.