mt48lc4m32b2tg-7-it Micron Semiconductor Products, mt48lc4m32b2tg-7-it Datasheet - Page 31

• Manufacturer Part Number: mt48lc4m32b2tg-7-it
• Description: 128mb X32 Sdram
• Manufacturer: Micron Semiconductor Products

Figure 23:
PRECHARGE
Power-Down
PDF: 09005aef80872800/Source: 09005aef80863355
128MbSDRAMx32_2.fm - Rev. K 9/07 EN
PRECHARGE Command
A0-A9, A11
The PRECHARGE command (Figure 23) is used to deactivate the open row in a partic-
ular bank or the open row in all banks. The bank(s) will be available for a subsequent row
access some specified time (
determines whether one or all banks are to be precharged, and in the case where only
one bank is to be precharged, inputs BA0 and BA1 select the bank. When all banks are to
be precharged, inputs BA0 and 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.
Power-down occurs if CKE is registered low coincident with a NOP or COMMAND
INHIBIT when no accesses are in progress (see Figure 24 on page 32). 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 either 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
BA0,1
RAS#
CAS#
WE#
CKE
CLK
A10
CS#
HIGH
VALID ADDRESS
Bank Selected
All Banks
ADDRESS
BANK
t
RP) after the precharge command is issued. Input A10
31
DON’T CARE
Micron Technology, Inc., reserves the right to change products or specifications without notice.
t
CKS).
©2001 Micron Technology, Inc. All rights reserved.
128Mb: x32 SDRAM
Register Definition