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[ASAHI KASEI]
[AK7716]
<M0057-E-01>
1999/09
- 17 -
5-5) External RAM interface
1)
Read/Write Interface Timing of External RAM (Static RAM)
(AVDD,DVDD,DVB=5.0V
±
5%, Ta=-40~85
°
C, CL=20pF, XTI=22.5792MHz)
Parameter
Symbol
min
Max
Units
Address delay time from OE Low to High (Writing)
Address delay time from OE High to Low (Reading)
Access time
Address set-up time
Data set time
Data hold time
Pulse width to write
2)
Read/Write Interface Timing of External RAM (Dynamic RAM) (Fast Page Mode Read Cycle / Early Write Cycle)
(AVDD, DVDD, DVB=5.0V
±
5%, Ta=-40~85
°
C, CL=20pF, XTI=22.5792MHz)
tAOEW
tAOER
tWCY
tWD
tDS
tDH
tWP
-15
-15
100
25
70
5
35
15
15
ns
ns
ns
ns
ns
ns
ns
Parameter
Symbol
min
Max
Units
Access time
Address delay time from OE ”L” to “H” (Writing)
Write command setup time
Write command hold time
Address delay time from OE ”H” to “L” (Reading)
Read command setup time
Read command hold time to CAS
Read command hold time to RAS
RAS preceded address setup time
RAS followed address hold time
CAS preceded address setup time
CAS followed address hold time
RAS to CAS delay time
RAS hold time
CAS to RAS precharge time
Data setup time
Data hold time after write
Pulse width of CAS “H”
Pulse width of CAS “L”
3)
Refresh Interface Timing of External RAM (Dynamic RAM) (CAS before RAS Refresh )
(AVDD, DVDD, DVB=5.0V
±
5%, Ta=-40~85
°
C, CL=20pF, XTI=22.5792MHz)
tRAC
tAOEW
tWCS
tWCH
tAOER
tRCS
tRCH
tRRH
tSURA
tHRA
tSUCA
tHCLCA
tRCD
tRSH
tCRP
tSUD
tHWLD
tWCH
tWCL
85
-15
20
20
-15
85
20
35
0
5
0
35
20
20
20
35
35
20
35
15
15
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Parameter
Symbol
Min
Max
Units
Read cycle
Pulse width of RAS “H”
Pulse width of RAS “L”
RAS Pre-charge / CAS hold time
CAS setup time at auto refresh
CAS hold time at auto refresh
tCRD
tWRH
tWRL
tRPC
tSUR
tHRRC
260
85
170
70
5
100
ns
ns
ns
ns
ns
ns