Discontinued (8/99 - last order; 12/99 - last ship)
IBM0364804 IBM0364164
IBM0364404 IBM03644B4
64Mb Synchronous DRAM - Die Revision B
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 neces-
sary precharge delay (tRP) must occur before the SDRAM can enter the power down mode. If a bank is acti-
vated 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 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 perform any
refresh operations, therefore the device can’t remain in Power Down mode longer than the Refresh period
(tREF) of the device.
The Power Down mode is exited by bringing CKE high. When CKE goes high, a No Operation Command (or
a 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
CLK
CKE
t
CK
t
CES
NOP
COMMAND
NOP
NOP
NOP
NOP
NOP
COMMAND
: “H” or “L”
©IBM Corporation. All rights reserved.
Use is further subject to the provisions at the end of this document.
19L3264.E35855A
1/28/99
Page 29 of 72
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