AS4C256K16FO
®
AC parameters common to all waveforms
(V = 5V 10%, GND = 0V, T = 0° C to +70° C)
CC
a
–25
–30
–35
–50
Standard
Symbol
Parameter
Random read or write cycle time
RAS precharge time
Min Max Min Max Min Max Min Max Unit Notes
tRC
45
15
25
4
–
–
65
25
30
5
–
–
70
25
35
6
–
–
85
25
50
10
15
15
10
50
5
–
–
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ms
ns
tRP
tRAS
tCAS
tRCD
tRAD
RAS pulse width
75K
–
75K
–
75K
–
75K
–
CAS pulse width
RAS to CAS delay time
RAS to column address delay time
10
8
17
13
–
15
10
10
30
5
20
14
–
16
11
10
35
5
24
17
–
35
25
–
6
7
tRSH(R) CAS to RAS hold time (read cycle)
7
tCSH
tCRP
tASR
tRAH
tT
RAS to CAS hold time
CAS to RAS precharge time
Row address setup time
Row address hold time
Transition time (rise and fall)
Refresh period
20
5
–
–
–
–
–
–
–
–
0
–
0
–
0
–
0
–
5
–
5
–
6
–
9
–
1.5
–
50
8
1.5
–
50
8
1.5
–
50
8
3
50
8
4,5
3
tREF
tCLZ
–
CAS to output in low Z
0
–
0
–
0
–
3
–
8
Read cycle
(V = 5V 10%, GND = 0V, T = 0° C to + 70° C)
CC
–30
a
–25
–35
–50
Standard
Symbol
Parameter
Min Max Min Max Min
Max Min Max Unit Notes
tRAC
tCAC
tAA
Access time from RAS
Access time from CAS
Access time from address
–
–
25
7
–
–
30
10
16
–
–
–
35
10
18
–
–
–
50
10
25
–
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
6
6,13
7,13
–
12
–
–
–
–
tAR(R) Column add hold from RAS
19
0
26
0
28
0
30
0
tRCS
tRCH
tRRH
tRAL
tCPN
tOFF
Read command setup time
Read command hold time to CAS
Read command hold time to RAS
Column address to RAS Lead time
CAS precharge time
–
–
–
–
0
–
0
–
0
–
0
–
9
9
0
–
0
–
0
–
0
–
12
4
–
16
3
–
18
4
–
25
5
–
–
–
–
–
Output buffer turn-off time
0
6
0
8
0
8
0
8
8,10
4/11/01; V.0.9.1
Alliance Semiconductor
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