HYB18L256160BF Datasheet, PDF (33/49 Pages) Infineon Technologies AG – DRAMs for Mobile Applications

HY[B/E]18L256160B[C/F]-7.5
256-Mbit Mobile-RAM
Functional Description
2.4.6.5 WRITE to PRECHARGE
A WRITE burst may be followed by, or truncated with a PRECHARGE command to the same bank, provided that
Auto Precharge was not activated. This is shown in Figure 34.
The PRECHARGE command should be issued t_WR after the clock edge at which the last desired data element of
the WRITE burst was registered. Additionally, when truncating a WRITE burst, DQM must be pulled to mask input
data presented during t_WR prior to the PRECHARGE command. Following the PRE-CHARGE command, a
subsequent ACTIVE command to the same bank cannot be issued until t_RP is met.
In the case of a WRITE 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 WRITE burst with Auto Precharge
enabled. The disadvantage of the PRECHARGE command is that it requires that the command and address
busses 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.
CLK
Command NOP
Address
A10
(AP)
DQM
DQ
WRITE
Ba A,
Col n
Dis AP
NOP
NOP
DI n
DI n+1
DI n+2
t_WR
NOP
PRE
t_RP
NOP
Ba A
Pre All
AP
Pre Bank A
ACT
Ba A,
Row a
Ba A, Col n = bank A, column n
DI n = Data In to column n
AP = Auto Precharge
Dis AP = Disable Auto Precharge
= Don't Care
Burst Length = 4 in the case shown.
3 subsequent elements of Data In are provided in the programmed order following DI n.
DI n+3 is masked due to DQM pulled HIGH during t_WR period prior to PRECHARGE command.
Figure 34 WRITE to PRECHARGE Timing
2.4.7 BURST TERMINATE
CLK
CKE
CS
RAS
CAS
WE
A0-A12
BA0,BA1
(High)
= Don't Care
The BURST TERMINATE command is used to truncate
READ or WRITE bursts (with Auto Precharge
disabled). The most recently registered READ or
WRITE command prior to the BURST TERMINATE
command will be truncated, as shown in Figure 18 and
Figure 30, respectively.
The BURST TERMINATE command is not allowed for
truncation of READ or WRITE bursts with Auto
Precharge enabled.
Figure 35 BURST TERMINATE Command
Data Sheet
33
V1.4, 2004-04-30