k4h280438d Samsung Semiconductor, Inc., k4h280438d Datasheet - Page 28

• Manufacturer Part Number: k4h280438d
• Description: 128mb D-die X4/8 Ddr Sdram
• Manufacturer: Samsung Semiconductor, Inc.

128Mb D-die(x4/8) DDR SDRAM
When the Read with Auto precharge command is issued, new command can be asserted at 3,4 and 5
respectively as follows,
operation BL/2 clock later 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. Once the precharge operation
has started the bank cannot be reactivated and the new command can not be asserted until the precharge
time(tRP) has been satisfied.
3.3.11 Read With Auto Precharge
CAS Latency=2
CAS Latency=2.5
If a read with auto-precharge command is initiated, the DDR SDRAM automatically enters the precharge
*1
READ+AP
Precharge
command
Asserted
: AP = Auto Precharge
READ
Active
< Burst Length=4, CAS Latency= 2, 2.5>
Command
DQS
DQ s
D Q S
DQ s
CK
CK
No AP
READ +
READ +
Illegal
Legal
AP
BANK A
ACTIVE
3
Table 6. Operating description when new command asserted
*1
0
For same Bank
Figure 19. Read with auto precharge timing
while read with auto precharge is issued
NOP
READ +
READ+
No AP
Illegal
Legal
1
AP
4
t
RAS(min.)
Auto Precharge
READ A
Begin Auto-Precharge
2
- 28 -
Illegal
Illegal
Illegal
Illegal
5
NOP
3
NOP
Dout 0 Dout 1 Dout 2 Dout 3
Legal
Legal
Legal
Legal
4
3
Dout 0 Dout 1 Dout 2 Dout 3
t
RP
NOP
For Different Bank
5
REV. 0.3 Jan.31. 2001
Legal
Legal
Legal
Legal
NOP
4
* Bank can be reactivated at the
completion of
6
NOP
precharge
7
Legal
Legal
Legal
Legal
5
NOP
8