.H 1 "FIREFOX RAM POWER"

This is a summary of the power requirements for the Firefox RAM board.

.H 2 "The RAM Array"

.H 3 "Stand-by Power"

.DL
.LI
Stand-by current - 5mA X 78 chips = 380 mA
.LI
Refresh current - ((60-5) mA X 78 chips)/(10 uS/.23 uS) = 120 mA
.LI
Total stand-by current - 500 mA
.LE

.H 3 "Active Power"

.DL
.LI
Chip access - 2 Accesses X ((70-5) mA X 39 chips)/(1.3 uS/.23 uS) = 900 mA
.LI
Nibble accesses - 6 Accesses X ((60-5) mA X 39 chips)/(1.3 uS/.06 uS) = 600 mA
.LI
Total active power - 500 mA + 900 mA + 600 mA = 2000 mA
.LE

An active RAM chip will draw (900 mA + 600 mA + (500/2) mA)/39 = 45 mA

.H 2 "NMOS Controller Power"

Stand-by - 1000 mA

If the MID_BUS buffers are not needed the controller will draw 500 mA more
when active (This is less than the buffers need).  The controller
will draw 30% more power when it is powered up at 0 degrees C.  This
will only be until it warms itself up.

.H 2 "TTL Power"

The TTL power was estimated by dividing the typical power by .8.

74AS2620 - 6 parts X 82 mA = 500 mA (Assumes output is a 1 about 70 percent
of the time.)

74F245 - 10 parts X 120 mA = 1200 mA

Total TTL power = 1700 mA

.H 2 "Total Board Power"

Stand-by - 500 mA + 1000 mA + 1200 mA = 2700 mA = 13.5 watts

Active - 2000 mA + 1000 mA + 1200 mA = 4200 mA = 21 watts

