is42s16402j Integrated Silicon Solution, Inc., is42s16402j Datasheet - Page 35

• Manufacturer Part Number: is42s16402j
• Description: 1 Meg Bits X 16 Bits X 4 Banks 64-mbit Synchronous Dynamic Ram
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S16402J
IS45S16402J
PRECHARGE
The PRECHARGE command (see figure) is used to deac-
tivate the open row in a particular bank or the open row in
all banks. T he bank(s) will be available for a subsequent row
access some specified time (t
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.
Integrated Silicon Solution, Inc. — www.issi.com
Rev. A
12/06/2011
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
rp
) after the PRECHARGE
t
NOP
CKS
Input buffers gated off
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
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