In a message dated 1/17/99 12:14:40 AM Pacific Standard Time, jones_gl@EFN.ORG
writes:

<<
 Today as i was installing decoupling caps on a circuit board i thought to
 myself: "Why dont the IC manufactures just incorperate a decoupling cap
 right in the ic itself?" Any one have any ideas?
  >>

Hi All,
Since I am in the business of making machines that make Ceramic capacitors
I'll field this one.
One problem with capacitors is that the value of the capacitor is directly
related to its size.  Integrating a capacitor of sufficient value to act as a
bypass cap would require that the IC's package grow by quite a bit.. Open your
Digikey catalog and check the values VS Size.
There are IC sockets that have caps built into them as long as your chip uses
a standard Power/Gnd pin configuration (Typically the lower left pin for
ground and the upper right pin for VCC)
One of the things my company is pioneering is the use of very thin Dielectrics
(less than 5 micron) to make very small chip caps.  If you half the thickness
of the dielectric you increase capacitance by a factor of 4. You also reduce
the voltage tolerance.  Life is made of trade-offs.  We are starting to see
the use of 01-02 chip capacitors.  Thats 10 thousandths by 20 thousandths.
They look like pepper when sprinkled on a sheet of paper.  I'm not sure how
they handle them but thats not my department!

Dave Duley
Dreitek Inc.
www.dreitek.com