ProASICPLUS Flash Family FPGAs
v5.9
2-29
Logic-Tile Contribution—Plogic
Plogic, the logic-tile component of AC power dissipation, is given by
Plogic = P3 * mc * Fs
where:
I/O Output Buffer Contribution—Poutputs
Poutputs, the I/O component of AC power dissipation, is given by
Poutputs = (P4 + (Cload * VDDP
2)) * p * Fp
where:
I/O Input Buffer's Buffer Contribution—Pinputs
The input’s component of AC power dissipation is given by
Pinputs = P8 * q * Fq
where:
PLL Contribution—Ppll
Ppll = P9 * Npll
where:
RAM Contribution—Pmemory
Finally, Pmemory, the memory component of AC power consumption, is given by
Pmemory = P6 * Nmemory * Fmemory * Ememory
where:
P3
=
1.4
μW/MHz is the average power consumption of a logic tile per MHz of its output toggling rate. The
maximum output toggling rate is Fs/2.
mc
=
the number of logic tiles switching during each Fs cycle
Fs
=
the clock frequency
P4
=
326
μW/MHz is the intrinsic power consumption of an output pad normalized per MHz of the output
frequency. This is the total I/O current VDDP.
Cload =
the output load
p
=
the number of outputs
Fp
=
the average output frequency
P8
=
29
μW/MHz is the intrinsic power consumption of an input pad normalized per MHz of the input
frequency.
q
=
the number of inputs
Fq
=
the average input frequency
P9
=
7.5 mW. This value has been estimated at maximum PLL clock frequency.
NPll
=
number of PLLs used
P6
=
175 W/MHz is the average power consumption of a memory block per MHz of the clock
Nmemory
=
the number of RAM/FIFO blocks
(1 block = 256 words * 9 bits)
Fmemory
=
the clock frequency of the memory
Ememory
=
the average number of active blocks divided by the total number of blocks (N) of the memory.
Typical values for Ememory would be 1/4 for a 1k x 8,9,16, 32 memory and 1/16 for a 4kx8,
9, 16, and 32 memory configuration
In addition, an application-dependent component to Ememory can be considered. For
example, for a 1kx8 memory configuration using only 1 cycle out of 2, Ememory = 1/4*1/2 = 1/8