NT5DS4M32EG Datasheet, PDF (16/46 Pages) NanoAmp Solutions, Inc. – 1M × 32 Bits × 4 Banks Double Data Rate Synchronous RAM With Bi-Directional Data Strobe and DLL

NanoAmp Solutions, Inc.
NT5DS4M32EG
Advance Information
AUTO-PRECHARGE OPERATION
The Auto precharge command can be issued by having column address A8 High when a Read or a Write command
is asserted into the DDR SDRAM. If A8 is low when Read or Write command is issued, normal Read or Write burst
operation is asserted and the bank remains active after the completion of the burst sequence. When the Auto
precharge command is activated, the active bank automatically begins to precharge at the earliest possible moment
during read or write cycle after tRAS (min) is satisfied.
Read with Auto Precharge
If a Read with Auto-precharge command is initiated, the DDR SDRAM automatically starts the precharge operation
on 2 clock previous to the end of burst from a Read with Auto-Precharge command when tRAS (min) is satisfied. If not,
the start point of precharge operation will be delayed until tRAS (min) is satisfied. The bank started the Precharge
operation once cannot be reactivated and the new command can not be asserted until the Precharge time (tRP) is
satisfied.
Figure 18: Read With Auto Precharge (Burst Length = 4, /CAS Latency = 3)
0
1
2
3
4
5
6
7
8
/CK
CK
Command
BANK A
AC TIVE
/CAS Latency = 3
DQS
DQ’s
NOP
NOP
READ A
Auto Prec har ge
NOP
tRCDR (min)
tRAS (min)
tRC(min)
NOP
NOP
NOP
NOP
* Bank can be reactiv ated at
tRP completion of tRP
Douta0 Douta1 Douta2 Douta3
Auto-Precharge start point
When the Read with Auto Precharge command is issued, new command can be asserted at T5, T6 and T7
respectively as follows.
Asserted Command
READ
READ + AP
ACTIVE
PRECHARGE
For Same Bank
T5
READ
(no AP)
READ + AP
Illegal
Legal
T6
READ
(no AP)
READ + AP
Illegal
Legal
T7
Illegal
Illegal
Illegal
Illegal
AP = Auto Precharge
For Different Bank
T5
T6
T7
Legal
Legal
Legal
Legal
Legal
Legal
Legal
Legal
Legal
Legal
Legal
Legal
Doc # 14-02-045 Rev A ECN 01-1118
16
The specifications of this device are subject to change without notice. For latest documentation see http://www.nanoamp.com.