Specifications ispLSI 5256VA
Power Consumption
Power consumption in the ispLSI 5256VA device de- on the complete group of four. The fast “high-speed”
pends on two primary factors: the speed at which the setting operates product terms at their normal full power
device is operating and the number of product terms consumption. For portions of the logic that can tolerate
used. The product terms have a fuse-selectable speed/ longer propagation delays, selecting the slower “low-
power tradeoff setting. Each group of four product terms power” setting will significantly reduce the power
has a single speed/power tradeoff control fuse that acts dissipation for these product terms. Figure 10 shows the
relationship between power and operating speed.
Figure 10. Typical Device Power Consumption vs fmax
400
350
300
250
200
150
100
ispLSI 5256VA
High Speed Mode
ispLSI 5256VA
Low Power Mode
0
20
40
60
80
100
120
140
fmax (MHz)
Notes: Configuration of 16 16-bit Counters
Typical Current at 3.3V, 25° C
I
can be estimated for the ispLSI 5256VA using the following equation:
CC
High Speed Mode: ICC = 30 + (# of PTs * 0.456) + (# of nets * Max. freq * 0.0039)
Low Power Mode: ICC = 30 + (# of PTs * 0.22) + (# of nets * Max. freq * 0.0039)
# of PTs = Number of Product Terms used in design
# of nets = Number of Signals used in device
Max. freq = Highest Clock Frequency to the device
The I
CC
estimate is based on typical conditions (V
CC
= 3.3V, room temperature) and an assumption of 2 GLB loads
is sensitive to operating conditions
on average exists. These values are for estimates only. Since the value of I
CC
and the program in the device, the actual I
CC
should be verified.
0127/5256va
16
LATTICE [ LATTICE SEMICONDUCTOR ]
