is42s16800-7tli Integrated Silicon Solution, Inc., is42s16800-7tli Datasheet - Page 27

• Manufacturer Part Number: is42s16800-7tli
• Description: 16m X 8, 8m X16 128mb Synchronous Dram
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S81600, IS42S16800
CHIP OPERATION
BANK/ROW ACTIVATION
Before any READ or WRITE commands can be issued
to a bank within the SDRAM, a row in that bank must be
“opened.” This is accomplished via the ACTIVE command,
which selects both the bank and the row to be activated
(see Activating Specific Row Within Specific Bank).
After opening a row (issuing an ACTIVE command), a READ
or WRITE command may be issued to that row, subject to
the t
the clock period and rounded up to the next whole number
to determine the earliest clock edge after the ACTIVE
command on which a READ or WRITE command can be
entered. For example, a t
125 MHz clock (8ns period) results in 2.25 clocks, rounded
to 3. This is reflected in the following example, which cov-
ers any case where 2 < [t
procedure is used to convert other specification limits from
time units to clock cycles).
A subsequent ACTIVE command to a different row in the
same bank can only be issued after the previous active
row has been “closed” (precharged). The minimum time
interval between successive ACTIVE commands to the
same bank is defined by t
A subsequent ACTIVE command to another bank can be
issued while the first bank is being accessed, which results
in a reduction of total row-access overhead.The minimum
time interval between successive ACTIVE commands to
different banks is defined by t
EXAMPLE: MEETING TRCD (MIN) WHEN 2 < [TRCD (MIN)/TCK] ≤ 3
Integrated Silicon Solution, Inc. — www.issi.com
Rev. 00A
08/06/08
rcd
specification. Minimum t
COMMAND
rcd
rc
rcd
.
specification of 18ns with a
rrd
CLK
(MIN)/t
rcd
.
should be divided by
ck
ACTIVE
] ≤ 3. (The same
T0
t
NOP
RCD
T1
ACTIVATING SPECIFIC ROW WITHIN SPE-
CIFIC BANK
BA0, BA1
A0-A11
NOP
T2
CKE
RAS
CAS
CLK
WE
CS
HIGH
READ or
WRITE
T3
DON'T CARE
BANK ADDRESS
ROW ADDRESS
T4
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