Preliminary
VG37648041AT
256M:x4, x8, x16
VIS
CMOS Synchronous Dynamic RAM
Data for any WRITE burst may be followed by a subsequent PRECHARGE command. To follow a WRITE with
out truncating the write burst, tWR should be met as shown in Figures 28 and 29.
Data for any WRITE burst may be truncated by a subsequent PRECHARGE command, as shown in Figures
30-33. Note that only the data -in pairs that are registered prior to the tWR period are written to the internal array,
and any subsequent data-in should be masked with DM (through one-half clock after the READ command). Fol-
lowing the PRECHARGE command, a subsequent command to the same bank can not be issued until tRP is
met.
In the case of a write burst being executed to completion, a PRECHARGE command issued at the optimum
time (as described above) provides the same operation that would result from the same burst with AUTO PRE-
CHARGE. The disadvantage of the PRECHARGE command is that it requires that the command and address
buses be available at the appropriate time to issue the command. The advantage of the PRECHARGE command
is that it can be used to truncate bursts.
Document : 1G5-0157
Rev.1
Page42
VML [ VANGUARD INTERNATIONAL SEMICONDUCTOR ]
