CMS3216LAH datasheet(35/46 Pages) FIDELIX

35 / 46 page

Rev0.2, Aug. 2006

CMS3216LAx-75Ex

command. This is shown in Figure 20. , where data n is the last

desired data element of a longer burst.

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 BS select the bank.

When all banks are to be precharged, inputs BS is

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.

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. .

CMS3216LAH 数据表(PDF) 35 Page - FIDELIX