HYB18L256160B Datasheet, PDF (37/58 Pages) Qimonda AG – DRAMs for Mobile Applications 256-Mbit Mobile-RAM

Data Sheet
2.4.8
PRECHARGE
The PRECHARGE command is used to deactivate (close) the
open row in a particular bank or the open row in all banks. The
bank(s) will be available for a subsequent row access a
specified time (t_RP) after the PRECHARGE command is
issued. Input A10 determines whether one or all banks are to
be precharged, and in the case where only one bank is to be
precharged, inputs BA0, BA1 select the bank. Otherwise
BA0, BA1 are treated as “Don’t Care”.
Once a bank has been precharged, it is in the idle state and
must be activated prior to any READ or WRITE commands
being issued to that bank. A PRECHARGE command will be
treated as a NOP if there is no open row in that bank, or if the
previously open row is already in the process of precharging.
HY[B/E]18L256160B[C/F]L-7.5
256-Mbit Mobile-RAM
FIGURE 36
PRECHARGE Command
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2.4.8.1 AUTO PRECHARGE
Auto Precharge is a feature which performs the same individual-bank precharge functions described above, but without
requiring an explicit command. This is accomplished by using A10 to enable Auto Precharge in conjunction with a specific
READ or WRITE command. A precharge of the bank/row that is addressed with the READ or WRITE command is automatically
performed upon completion of the READ or WRITE burst. Auto Precharge is non persistent in that it is either enabled or
disabled for each individual READ or WRITE command. Auto Precharge ensures that the precharge is initiated at the earliest
valid stage within a burst. The user must not issue another command to the same bank until the precharge (t_RP) is completed.
This is determined as if an explicit PRECHARGE command was issued at the earliest possible time, as described for each
burst type.
Rev. 1.73, 2006-09
37
01302004-CZ2R-J9SE