DS2251T
AC CHARACTERISTICS—EXPANDED BUS MODE TIMING SPECIFICATIONS
(continued)
(VCC = 5V ±10%, TA = 0˚C to +70˚C.)
# PARAMETER
SYMBOL MIN
MAX
UNITS
19 ALE Low to Valid Data In
At 12MHz
At 16MHz
tALLVD
8CLK - 150
ns
8tCLK - 90
20
Valid Address to Valid Data
In
At 12MHz
At 16MHz
tAVDV
9tCLK - 165
ns
9tCLK - 105
21 ALE Low to RD or WR Low
tALLRDL
3tCLK -50 3tCLK + 50
ns
22 Address Valid to RD or WR Low
tAVRDL
4tCLK -130
ns
23 Data Valid to WR Going Low
tDVWRL
tCLK - 60
ns
At 12MHz
7tCLK - 150
24 Data Valid to WR High
tDVWRH
ns
At 16MHz
7tCLK - 90
25 Data Valid after WR High
tWRHDV
tCLK - 50
ns
26 RD Low to Address Float
tRDLAZ
0
ns
27 RD or WR High to ALE High
tRDHALH
tCLK - 40
tCLK + 50
ns
EXPANDED PROGRAM MEMORY READ CYCLE
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