Data Sheet
64Mbit – High Speed SDRAM
8Mx8, 4Mx16 HSDRAM
Symbol
Parameter
Min
-7.5
Max
4.6
6.0
15.0
13.75
-
-
-
-
4.6
7.0
-
-
-
-
-
-
Units
Notes
Read and Write Parameters
t
AC3
t
AC2
t
AC1
t
OH3
t
OH2
t
OH1
t
LZ
t
HZ2
t
HZ1
t
DQZ
t
DS
t
DH
t
DPL
t
DAL
t
DQW
Clock Access Time, CL = 3
Clock Access Time, CL = 2
Clock Access Time, CL = 1 (-7.5 device)
Clock Access Time, CL = 1 (-7.5F device)
Data Output Hold Time (CL=3)
Data Output Hold Time (CL=2)
Data Output Hold Time (CL=1)
Data Output to Low-Z Time
Data Output to High-Z Time (CL=2, 3)
Data Output to High-Z Time (CL=1)
DQM Data Output Disable Time
Data Input Set-Up Time
Data Input Hold Time
Data Input to Precharge
Data Input to ACTV/Refresh
Data Write Mask Latency
-
-
-
2.7
3.0
3.5
1
-
-
2
1.5
0.8
15
30
0
ns
ns
ns
ns
ns
ns
ns
ns
ns
CLK
ns
ns
ns
ns
CLK
4
3
3
1,2,8
1,2
1,2
Refresh Parameters
t
REF
t
SREX
Notes:
1.
2.
3.
4.
5.
6.
Access time is measured at 1.4V (LVTTL) at max clock rate for the CAS latency specified. See AC Test Load.
Access time is based on a clock rise time of 1ns. If clock rise time is longer than 1ns, then (trise/2-0.5) ns must be added to the access time.
Referenced to the time at which the output achieves an open circuit condition.
t
DAL
is equal to t
DPL
+ t
RP
.
4096 cycles.
Any time that the refresh period has been exceeded, a minimum of two Auto-Refresh (CBR) commands must be given to “wake up” the device.
completed until t
RC
is satisfied once the Self-Refresh Exit command is registered.
Refresh Period
Self Refresh Exit Time
-
2CLK+t
RC
64
-
ms
ns
5, 6
7
7.
Self-Refresh exit is a synchronous operation and begins on the 2nd positive clock edge after CKE returns high. Self-Refresh Exit is not
8.
For 4Mx16 devices, the Clock Access Time (CL=3) is 5.0 ns.
Enhanced Memory Systems Inc., 1850 Ramtron Dr., Colo Spgs, CO 80921
PHONE: (800) 545-DRAM; FAX: (719) 488-9095;
http://www.edram.com
1999 Enhanced Memory Systems. All rights reserved.
The information contained herein is subject to change without notice.
Revision 1.1
Page 7 of 10
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
