HYB25D256[400/800/160]B[T/C](L)
256-Mbit Double Data Rate SDRAM
Functional Description
3) Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses and no register
accesses are in progress.
Read: A Read burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Write: A Write burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Read with Auto Precharge Enabled: See 10)
Write with Auto Precharge Enabled: See 10)
.
.
4) AUTO REFRESH and Mode Register Set commands may only be issued when all banks are idle.
5) A BURST TERMINATE command cannot be issued to another bank; it applies to the bank represented by the current state
only.
6) All states and sequences not shown are illegal or reserved.
7) Reads or Writes listed in the Command/Action column include Reads or Writes with Auto Precharge enabled and Reads
or Writes with Auto Precharge disabled.
8) Requires appropriate DM masking.
9) Concurrent Auto Precharge:
This device supports “Concurrent Auto Precharge”. When a read with auto precharge or a write with auto precharge is
enabled any command may follow to the other banks as long as that command does not interrupt the read or write data
transfer and all other limitations apply (e.g. contention between READ data and WRITE data must be avoided). The
minimum delay from a read or write command with auto precharge enable, to a command to a different banks is
summarized in Table 11.
10) A Write command may be applied after the completion of data output.
Table 11
Truth Table 5: Concurrent Auto Precharge
From Command
To Command (different bank)
Minimum Delay with Concurrent
Auto Precharge Support
Unit
WRITE w/AP
Read or Read w/AP
Write to Write w/AP
Precharge or Activate
Read or Read w/AP
Write or Write w/AP
Precharge or Activate
1 + (BL/2) + tWTR
tCK
tCK
tCK
tCK
tCK
tCK
BL/2
1
Read w/AP
BL/2
CL (rounded up) + BL/2
1
Data Sheet
52
Rev. 1.21, 2004-07
02102004-TSR1-4ZWW
QIMONDA [ QIMONDA AG ]
