Logic Design for ArrayBased Circuitsby Donnamaie E. WhiteCopyright © 1996, 2001, 2002 Donnamaie E. White 


Power ConsiderationsLast Edit July 22, 2001
Step 10: Determine ECL Static Power PEOThe equation used by the AMCC MacroMatrix ERC software to compute ECL static power dissipation for ECL outputs is:
The 1.3V term represents the average between VOH and VOL. This is considered to be the statistical worstcase for this function If there is more than one termination, the power for each type of termination is computed and summed to find the total PECL outputs
ECL Output Termination CurrentTable 715 provides the ECL output termination currents used by the AMCC MacroMatrix ERC software. The currents shown are the average current (average of IOH and IOL) AMCC automated ECL static power is computed with the 50 or 25 ohm termination under the assumption of 50% terminations active. This is because AMCC provides macros that drive 50 ohm loads and macros that drive 25 ohm loads. These assumptions may vary with the vendor. Table 715 ECL Termination Current
* the average current (average of IOH and IOL) for termination to 2V * When 50 ohm or 25 ohm Terminations are Not UsedResistive loads that differ from that used by automation software will require manual computation. These loads should be identified when performing design submission to any vendor. If other ECL output load resistances are used, the actual current value must be computed for use in the ECL static power equation. For a 2V termination, to find the average current in mA, use the following equation.
* When VT Ê 2VFor other termination voltages, an adjustment to the power dissipation computation must be made by the designer. For a termination voltage VT, to find the average current in mA, use the following equation.
* Darlington ECL OutputsDarlington ECL outputs are treated as a standard ECL outputs for static power computations. * OnChip Series TerminationThere is no IOEF output current for onchip series termination ECL output macros. All current (power) dissipated is specified in the macro documentation. Step 11: Sum the Result  Total DC powerSum the results of the macro and overhead current power computations with any ECL output macro static power dissipation to obtain the total worstcase DC power dissipation for the circuit:
The result is the total worstcase DC power dissipated by the circuit on the target array. Exercises


Copyright @ 2001,
2002 Donnamaie E. White, White
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