Specifications GAL22V10
fmax Descriptions
C L K
CLK
LOGIC
ARRAY
LOGIC
ARR AY
REGISTER
REGISTER
t
s u
tc o
fmax with External Feedback 1/(tsu+tco)
t
cf
pd
t
Note: fmax with external feedback is cal-
culated from measured tsu and tco.
fmax with Internal Feedback 1/(tsu+tcf)
CLK
Note: tcf is a calculated value, derived by sub-
tracting tsu from the period of fmax w/internal
feedback (tcf = 1/fmax - tsu). The value of tcf is
used primarily when calculating the delay from
clocking a register to a combinatorial output
(through registered feedback), as shown above.
For example, the timing from clock to a combi-
natorial output is equal to tcf + tpd.
LOGIC
REGISTER
ARRAY
t
su + th
fmax with No Feedback
Note: fmax with no feedback may be less
than 1/(twh + twl). This is to allow for a
clock duty cycle of other than 50%.
14
LATTICE [ LATTICE SEMICONDUCTOR ]
