IS45S32800D-6BLA1 ISSI, Integrated Silicon Solution Inc, IS45S32800D-6BLA1 Datasheet - Page 37

• Manufacturer Part Number: IS45S32800D-6BLA1
• Manufacturer: ISSI, Integrated Silicon Solution Inc
• Type: SDRAMr

Specifications of IS45S32800D-6BLA1

• Organization: 8Mx32
• Density: 256Mb
• Address Bus: 13b
• Access Time (max): 6.5/5.4ns
• Maximum Clock Rate: 166MHz
• Operating Supply Voltage (typ): 3.3V
• Package Type: TSOP-II
• Operating Temp Range: -40C to 85C
• Operating Supply Voltage (max): 3.6V
• Operating Supply Voltage (min): 3V
• Supply Current: 180mA
• Pin Count: 90
• Mounting: Surface Mount
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Compliant

IS42S32800D, IS45S32800D
WRITE COMMAND
WRITES
WRITE bursts are initiated with a WRITE command, as
shown in WRITE Command diagram.
The starting column and bank addresses are provided with
the WRITE command, and auto precharge is either enabled
or disabled for that access. If auto precharge is enabled,
the row being accessed is precharged at the completion of
the burst. For the generic WRITE commands used in the
following illustrations, auto precharge is disabled.
During WRITE bursts, the first valid data-in element will be
registered coincident with the WRITE command. Subsequent
data elements will be registered on each successive posi-
tive clock edge. Upon completion of a fixed-length burst,
assuming no other commands have been initiated, the
DQs will remain High-Z and any additional input data will
be ignored (see WRITE Burst). A full-page burst will con-
tinue until terminated. (At the end of the page, it will wrap
to column 0 and continue.)
Data for any WRITE burst may be truncated with a subse-
quent WRITE command, and data for a fixed-length WRITE
burst may be immediately followed by data for a WRITE
command. The new WRITE command can be issued on
any clock following the previous WRITE command, and the
data provided coincident with the new command applies to
the new command.
Integrated Silicon Solution, Inc. - www.issi.com
Rev. C
12/01/09
BA0, BA1
A9, A11
A0-A8
CKE
RAS
CAS
CLK
A10
WE
CS
HIGH
COLUMN ADDRESS
AUTO PRECHARGE
NO PRECHARGE
BANK ADDRESS
An example is shown in WRITE to WRITE diagram. Data n
+ 1 is either the last of a burst of two or the last desired of
a longer burst. The SDRAM uses a pipelined architecture
and therefore does not require the 2n rule associated with
a prefetch architecture.AWRITE command can be initiated
on any clock cycle following a previous WRITE command.
Full-speed random write accesses within a page can be
performed to the same bank, as shown in Random WRITE
Cycles, or each subsequent WRITE may be performed to
a different bank.
Data for any WRITE burst may be truncated with a subse-
quent READ command, and data for a fixed-length WRITE
burst may be immediately followed by a subsequent READ
command. Once the READ com mand is registered, the
data inputs will be ignored, and WRITEs will not be ex-
ecuted. An example is shown in WRITE to READ. Data n
+ 1 is either the last of a burst of two or the last desired
of a longer burst.
Data for a fixed-length WRITE burst may be followed
by, or truncated with, a PRECHARGE command to the
same bank (provided that auto precharge was not acti-
vated), and a full-page WRITE burst may be truncated
with a PRECHARGE command to the same bank. The
PRECHARGE command should be issued t
clock edge at which the last desired input data element
is registered. The auto precharge mode requires a t
at least one clock plus time, regardless of frequency. In
addition, when truncating a WRITE burst, the DQM signal
must be used to mask input data for the clock edge prior
to, and the clock edge coincident with, the PRECHARGE
command. An example is shown in the WRITE to PRE-
CHARGE diagram. Data n+1 is either the last of a burst
of two or the last desired of a longer burst. Following the
PRECHARGE command, a subsequent command to the
same bank cannot be issued until t
In the case of a fixed-length burst being executed to comple-
tion, a PRECHARGE command issued at the optimum
time (as described above) provides the same operation that
would result from the same fixed-length burst with auto
precharge.The disadvantage of the PRECHARGE command
is that it requires that the command and address buses be
available at the appropriate time to issue the command;the
advantage of the PRECHARGE command is that it can be
used to truncate fixed-length or full-page bursts.
Fixed-length or full-page WRITE bursts can be truncated
with the BURST TERMINATE command. When truncat-
ing a WRITE burst, the input data applied coincident with
the BURST TERMINATE command will be ignored. The
last data written (provided that DQM is LOW at that time)
will be the input data applied one clock previous to the
BURST TERMINATE command. This is shown in WRITE
Burst Termination, where data n is the last desired data
element of a longer burst.
rp
is met.
dpl
after the
dpl
37
of