> From: Ravinder Ajmani[SMTP:firstname.lastname@example.org]
> Sent: Friday, October 31, 1997 11:50 AM
> To: si-list@silab.Eng.Sun.COM
> Subject: Re: Re: [SI-LIST] : Decoupling capacitor selection &
> I have been studying the effects of increased power/ground capacitance
> on noise
> and EMI, and also to determine if I can use this option to reduce the
> number of
> capacitors on the board. I have used FR4 with thickness of 3 mils,
> and also
> Zycon material, which is 2 mils thick but is still FR4, and hence
> provide enough capacitance to make any significant difference. I have
> with our raw card fabricators and none could provide me any details
> about high
> dielectric constant material.
> I will be interested in using the EmCap material in my experiment. I
> appreciate if Todd can inform me who in California has the capability
> fabricate boards with this material.
> Regards, Ravinder
> EMC & Signal Integrity Engineer
> PCB Development and Design Department
> Voice : (408) 256-7956 T/L : 276-7956 Fax : (408)
> Email: email@example.com
> 10/29/97 05:11 AM
> Please respond to owner-si-list@silab.Eng.Sun.COM @ internet
> cc: si-list@silab.Eng.Sun.COM @ internet
> Subject: Re: [SI-LIST] : Decoupling capacitor selection & placemen
> How does everyone feel about power/ground distributed
> Zycon originally developed ZBC2000 - a thin FR4 (.002")
> core with a capacitance of ~500pf/sq in (usually 2 cores are
> used) -
> as a decoupling capacitor replacement or adjunct.
> HADCO and Polyclad have developed EmCap - a 0.004" Ceramic / FR4
> power/ground core with 2750pf/sq in - as the next generation.
> I have been doing work to predict the ability of both these
> to replace discrete capacitors in our customers boards and would
> to hear some honest thoughts and feedback.
> FYI - I'm an EE working at HADCO. I work with the electrical
> issues in
> PWB - impedance, capacitance, layout, etc. - more or less in
> house SI.
> Todd DeRego