Power Considerations
Last Edit July 22, 2001
Total Power Dissipation
Add the DC power computation result to the AC power computation result.
Pd = PdDC + PdAC
The result is the worstcase power dissipation to be used in computing
junction temperature.
Depending on the array series, one of the terms may be zero or close
enough to zero to discount.
Exercises
 Is AC power a factor in the array series of interest? (Use the same
series used in the DC power exercises.)
 What equation is used by the array vendor you have chosen?
 AMCC Q20000 Series: Continue the problem started in the DC power
exercises and add AC power to the DC power already computed for the
circuit. The number of input macros is 84. The number of internal macros
is 112. There are no Darlington output macros. Assume all macros switch
at 500MHz (Note: Is there a pulse width violation for any macros at
this speed?)
 Compare both versions of the above problem as described earlier. Which
one is best?
