Specifications GAL16LV8
fmax Descriptions
C L K
CLK
LOGIC
ARR AY
REGISTER
LOGIC
ARRAY
REGISTER
t
s u
tc o
fmax with External Feedback 1/(tsu+tco)
Note: fmax with external feedback is calculated from measured
tsu and tco.
t
cf
pd
CLK
t
fmax with Internal Feedback 1/(tsu+tcf)
LOGIC
REGISTER
ARRAY
Note: tcf is a calculated value, derived by subtracting 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 combinatorial output is equal to tcf + tpd.
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%.
15
LATTICE [ LATTICE SEMICONDUCTOR ]
