IBMN312164CT3
IBMN312404CT3
IBMN312804CT3
128Mb Synchronous DRAM - Die Revision B
Preliminary
Power Down Mode
In order to reduce standby power consumption, two power down modes are available: Precharge and Active
Power Down mode. To enter Precharge Power Down mode, all banks must be precharged and the necessary
precharge delay (t ) must occur before the SDRAM can enter the power down mode. If a bank is activated
RP
but not performing a Read or Write operation, Active Power Down mode will be entered. (Issuing a Power
Down Mode Command when the device is performing a Read or Write operation causes the device to enter
Clock Suspend mode. See the following Clock Suspend section.) Once the Power Down mode is initiated by
holding CKE low, all of the receiver circuits except CKE are gated off. The Power Down mode does not per-
form any refresh operations, therefore the device can’t remain in Power Down mode longer than the Refresh
period (t
) of the device.
REF
The Power Down mode is exited by bringing CKE high. When CKE goes high, a No Operation Command (or
Device Deselect Command) is required on the next rising clock edge.
Power Down Mode Exit Timing
Tm
Tm+1
Tm+2
Tm+3
Tm+4
Tm+5
Tm+6
Tm+7
Tm+ 8
CK
t
CK
CKE
t
CES(min)
NOP
COMMAND
NOP
NOP
NOP
NOP
NOP
COMMAND
: “H” or “L”
©IBM Corporation. All rights reserved.
06K7582.H03335A
01/01
Use is further subject to the provisions at the end of this document.
Page 26 of 66
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