![](http://datasheet.mmic.net.cn/370000/MC-42S4LFG64S_datasheet_16719274/MC-42S4LFG64S_10.png)
10
MC-42S4LFG64S
Hyper Page Mode (EDO)
Parameter
Symbol
t
RAC
= 50 ns
t
RAC
= 60 ns
Unit
Notes
MIN.
MAX.
MIN.
MAX.
Read / Write cycle time
t
HPC
20
25
ns
1
/RAS pulse width
t
RASP
50
125,000
60
125,000
ns
/CAS pulse width
t
HCAS
8
10,000
10
10,000
ns
/CAS precharge time
t
CP
7
10
ns
Access time from /CAS precharge
t
ACP
30
35
ns
/CAS precharge to /WE delay time
t
CPWD
41
52
ns
2
/RAS hold time from /CAS precharge
t
RHCP
30
35
ns
Read modify write cycle time
t
HPRWC
52
66
ns
Data output hold time
t
DHC
5
5
ns
/OE to /CAS hold time
t
OCH
5
5
ns
3
/OE precharge time
t
OEP
5
5
ns
Output buffer turn-off delay from /WE
t
WEZ
0
10
0
13
ns
4,5
/WE pulse width
t
WPZ
7
10
ns
5
Output buffer turn-off delay from /RAS
t
OFR
0
10
0
13
ns
4,5
Output buffer turn-off delay from /CAS
t
OFC
0
10
0
13
ns
4,5
Notes 1.
t
HPC (MIN.)
is applied to /CAS access.
2.
If t
WCS
≥
t
WCS (MIN.)
, the cycle is an early write cycle and the data out will remain Hi-Z through the entire
cycle. If t
RWD
≥
t
RWD (MIN.)
, t
CWD
≥
t
CWD (MIN.)
, t
AWD
≥
t
AWD (MIN.)
and t
CPWD
≥
t
CPWD (MIN.)
, the cycle is a read modify
write cycle and the data out will contain data read from the selected cell. If neither of the above conditions
is met, the state of the data out is indeterminate.
3.
/WE : inactive (in read cycle)
/CAS : inactive, /OE : active ...... t
CHO
is effective.
/CAS, /OE : active ...... t
OCH
is effective.
4.
t
OFC (MAX.)
, t
OFR (MAX.)
and t
WEZ (MAX.)
define the time when the output achieves the conditions of Hi-Z and is
not referenced to V
OH
or V
OL
.
5.
To make DQs to Hi-Z in read cycle, it is necessary to control /RAS, /CAS, /WE, /OE as follows. The effective
specification depends on state of each signal.
(1) Both /RAS and /CAS are inactive (at the end of the read cycle)
/WE : inactive, /OE : active
t
OFC
is effective when /RAS is inactivated before /CAS is inactivated.
t
OFR
is effective when /CAS is inactivated before /RAS is inactivated.
The slower of t
OFC
and t
OFR
becomes effective.
(2) Both /RAS and /CAS are active or either /RAS or /CAS is active (in read cycle)
/WE, /OE : inactive ...... t
OEZ
is effective.
Both /RAS and /CAS are inactive or /RAS is active and /CAS is inactive (at the end of read cycle)
/WE, /OE : active and either t
RRH
or t
RCH
must be met ...... t
WEZ
and t
WPZ
are effective.
The faster of t
OEZ
and t
WEZ
becomes effective.
The faster of (1) and (2) becomes effective.