Power Considerations
Last Edit July 22, 2001
Step 5: Compute AC Power For all ECL Input Macros
Using the counts from step 4, compute the AC power dissipated by the
ECL inputs used in the circuit. For AMCC arrays, use:
PacI = f * n * 3.25 microwatts
where
f = frequency of operation in MHz
n = number of ECL input macros
conversion factor = 3.25 microwatt/macroMHz for Q20000 Series
 Compute the AC power due to those input macros switching at the fastest
frequency.
 Compute the AC power due to those macros switching at the next fastest
frequency.
 Repeat until all ECL input macros are accounted for and sum the results.
Step 6: Find the Number of Internal Macros
Using the macro occurrence worksheet, find the number of internal macros.
For AMCC customers, the number of internal macros can be determined from
the AMCC Population ERC report.
Step 7: Compute AC Power For all Internal Macros
Using the count from step 6, estimate the AC power dissipated by the
internal macros used in the circuit:
PacI = 0.20 * f * n * 3.25 microwatts
where
f = maximum frequency of operation in MHz
n = number of internal macros
0.2 = 20% switching
conversion factor = 3.25 microwatt/macroMHz for Q20000 Series
Step 8: Sum All Components of AC Power
Sum the results together and convert to watts (or to the same units
as was used for DC power). This equation provides an estimate of the worstcase
AC power dissipation for the Q20000 array.
PdAC = PacI + Pacinternal + PacDARoutputs
Use the same equation for military and commercial computations.
