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HYB18L256160B Datasheet, PDF (35/58 Pages) Qimonda AG – DRAMs for Mobile Applications 256-Mbit Mobile-RAM
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Data Sheet
HY[B/E]18L256160B[C/F]L-7.5
256-Mbit Mobile-RAM
2.4.6.4 WRITE to READ
A WRITE burst may be followed by, or truncated with a READ command. The READ command can be performed to the same
or a different (active) bank. With the registration of the READ command, data inputs will be ignored and no WRITE will be
performed, as shown in Figure 33.
FIGURE 33
WRITE to READ Timing
&/ .
&RP PD QG :5 ,7(
$GGUH VV
%D$ 
&R OQ 
12 3 
12 3 
5( $'
%D$ 
&R OE 
'4  ',Q 
'4  ',Q 
',Q   ',Q 
:ULWHGDWD
DUHLJQR UHG
',Q   ',Q 
12 3 
12 3 
12 3 
12 3 
&/   
+LJ K=
'2 E  '2 E  '2 E 
&/   
+LJK =
'2 E  ',E   
%D$&R OQ E  E DQN$FR OX PQ Q E  
',Q 'D WD,QWRFROXPQ Q'2 E 'DWD 2XWIUR PFROX PQ E
'R Q W&D UH
%XUVW/HQJWK LQ WK HFDVHVKR ZQ 
VXEVHTX HQWHOH PHQWVRI'D WD,Q 2 XW DUHSURYLG HG LQWKHSURJUD PPH GRUGHUIROORZLQ J ',Q ' 2 E 
',Q LV LJ Q RUHGGXH WR5 ($ 'FRPP DQG 1R '4 0PDV NLQJ UHTXLUHGDWWKLV SRLQ W
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 tWR 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
tWR prior to the PRECHARGE command. Following the PRE-CHARGE command, a subsequent ACTIVE command to the
same bank cannot be issued until tRP 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.
Rev. 1.73, 2006-09
35
01302004-CZ2R-J9SE
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