Datasheet
Interfaces
Intel
®
Xeon
®
Processor C5500/C3500 Series
Datasheet, Volume 1 February 2010
60 Order Number: 323103-001
2.1.14.2.3 Precharge Power Down
If power-down occurs when all banks are idle, this mode is referred to as precharge
power-down. If power-down occurs when there is a row active in any bank, this mode
is referred to as active power-down.
A DRAM in power-down deactivates its input and output buffers, excluding CK, CK#,
ODT, and CKE.
The Integrated Memory Controller will not actively seek precharge power down. If
requests stop for the power down delay, the channel will de-assert CKE. If page closing
is enabled, CKE will be asserted as needed to issue precharges to close pages when
their idle timers expire.
If the closed page operation is selected, pages will be closed when CKE is asserted. If
open-page operation is selected, pages are closed according to an adaptive policy. If
there were many page hits recently, it is less likely that all pages will happen to be
closed when the rank CKE timeout expires.
2.1.14.3 Dynamic DRAM Interface Power Savings Features
The following table defines the IO power saving features. The 1 and 2 DCLK on/off
times do not affect command issue and are non-critical to performance. The on/off time
is quoted so that power savings can be accurately evaluated.
Table 21. DRAM Power Savings Exit Parameters
Parameter Symbol
Exit Times
(DCLKs = tCK)
Command to active power down tRDPDEN
tRL + 5
This is the delay for reads, Applies it to all commands.
RDA would be used in the auto-precharge case, which
is slightly longer.
Active Power Down tDPEX
Active or Precharge Power down to
any command
tXP 3 for 800, 4 for 1067 and 1333
ODT on (power down mode) tAONPD ~2.5ns
ODT off (power down mode) tAOFPD ~6.5ns
Self Refresh timing Reference? tSXR 250
Self Refresh to commands tXSDLL
512
MC will apply tXSRD delay before issuing any
commands.
Min CKE hi or lo time tCKE Three clocks
Table 22. Dynamic IO Power Savings Features (Sheet 1 of 2)
Power Savings Feature On Condition Time to Turn Off Off Condition Time to Turn On
Power down mixers and amps in the
Address and Command Phase
Interpolators.
DRAMs in self
refresh
10 DCLK S3 exit request < 1 usec
Tristate Address and Command drivers
Deselect command
is driven
1 DCLK
Any other command
is driven
1 DCLK
Tristate Data drivers
No data to drive.
Derived from write
CAS.
0 DCLK Driving data 0 DCLK