Embedded Capacitors

Capacitors in PCB can be formed using special layers made of various dielectric material in a multilayer PCB. Today BC2000 a capacitive laminate from Hadco/Sanmina is the most common.

Products from DuPont, 3M,Shipley and Mitsui Metals are also developed.

The area required to implement a capacitance value in a PCB limits applications to small capacitance values.

Capacitance formula: C=E,*A/t, C =Capacitance E, =Dielectric Constant, A = Area, t = thickness

To consider:
  • Surface mounted discrete capacitors are ineffective above 1 GHz
  • Low impedance and high capacitance at high frequencies
  • Impedance is more critical than capacitance at high frequencies
  • Lowe power bus noise can result in reduced radiated emission
Sample of data for different Capacitance material

 

 

 

 

 

 

 

More informations:

http://solutions.3m.com/wps/portal/3M/en_US/EmbeddedCapacitanceMaterial/Home/Learn2/ProductInformation/

http://www2.dupont.com/Interra/en_US/products/laminate/index.html