is42s16400b1 Integrated Silicon Solution, Inc., is42s16400b1 Datasheet - Page 31

• Manufacturer Part Number: is42s16400b1
• Description: 1 Meg Bits X 16 Bits X 4 Banks 64-mbit Synchronous Dynamic Ram - Integrated Silicon Solution, Inc
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S16400B1
PRECHARGE
The PRECHARGE command (see figure) 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 (t
the PRECHARGE command is issued. Input A10 deter-
mines 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 com-
mands being issued to that bank.
Integrated Silicon Solution, Inc. — www.issi.com —
Rev. A
12/09/03
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 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 t
POWER-DOWN
CKS
COMMAND
). See figure below.
CKE
CLK
All banks idle
Enter power-down mode
t
NOP
CKS
RP
Input buffers gated off
) after
1-800-379-4774
PRECHARGE Command
Exit power-down mode
BA0, BA1
A0-A9, A11
CKE
RAS
CAS
CLK
A10
WE
CS
t
HIGH - Z
CKS
NOP
DON'T CARE
BANK ADDRESS
BANK SELECT
ACTIVE
ALL BANKS
t
t
t
RCD
RAS
RC
ISSI
31
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