IS42S16100 Integrated Silicon Solution, IS42S16100 Datasheet - Page 35

• Manufacturer Part Number: IS42S16100
• Description: 512K Words x 16Bits x 2 Banks Synchronous Dynamic RAM
• Manufacturer: Integrated Silicon Solution

IS42S16100
Clock Suspend
When the CKE pin is dropped from HIGH to LOW during
a read or write cycle, the IS42S16100 enters clock suspend
mode on the next CLK rising edge. This command reduces
the device power dissipation by stopping the device
internal clock. Clock suspend mode continues as long as
the CKE pin remains low. In this state, all inputs other than
CKE pin are invalid and no other commands can be
executed. Also, the device internal states are maintained.
When the CKE pin goes from LOW to HIGH clock suspend
mode is terminated on the next CLK rising edge and
device operation resumes.
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. C
11/01/01
Bank Active Command Interval
When the selected bank is precharged, the period trp has
elapsed and the bank has entered the idle state, the bank
can be activated by executing the active command. If the
other bank is in the idle state at that time, the active
command can be executed for that bank after the period
t
active state. When a bank active command has been
executed, a precharge command must be executed for
RRD
CAS latency = 3
CAS latency = 2, burst length = 4
has elapsed. At that point both banks will be in the
COMMAND
COMMAND
COMMAND
CKE
CLK
CLK
CLK
I/O
BANK ACTIVE (BANK 0)
BANK ACTIVE (BANK 0)
READ (BANK 0)
READ 0
ACT 0
ACT 0
t
t
RRD
RCD
D
OUT
CLOCK SUSPEND
BANK ACTIVE (BANK 1)
BANK ACTIVE (BANK 0)
0
READ 0
ACT 1
that bank within the ACT to PRE command period (t
max). Also note that a precharge command cannot be
executed for an active bank before t
After a bank active command has been executed and the
trcd period has elapsed, read write (including auto-
precharge) commands can be executed for that bank.
The next command cannot be executed until the recovery
period (t
Since this command differs from the self-refresh command
described previously in that the refresh operation is not
performed automatically internally, the refresh operation
must be performed within the refresh period (tref). Thus
the maximum time that clock suspend mode can be held
is just under the refresh cycle time.
D
OUT
1
CKA
) has elapsed.
D
OUT
2
D
OUT
3
RAS
(min) has elapsed.
ISSI
RAS
35
®