CMS4A16LAx–75Ex
command. This is shown in Figure 20. , where data n is the last
desired data element of a longer burst.
POWER-DOWN
Power-down occurs if CKE is registered LOW coincident with
a NOP or COMMAND INHIBIT when no accesses are in
progress. If power-down occurs when all banks are idle, this
mode is referred to as precharge power-down; if power-down
occurs when there is a row active in any bank, this mode is
referred to as active power-down. Entering power-down
deactivates the input and output buffers, excluding CKE, for
maximum power savings while in standby. The device may
not remain in the power-down state longer than the refresh
period (64ms) since no refresh operations are performed in
this mode. The power-down state is exited by registering a
NOP or COMMAND INHIBIT and CKE HIGH at the desired
clock edge(meeting tCKS). See Figure 22. .
PRECHARGE
The PRECHARGE command (see Figure 21. ) is used to
deactivate 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 some specified time (tRP) 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.
When all banks are to be precharged, inputs 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.
35
Rev. 0.5, May. ‘07
FIDELIX [ FIDELIX ]
