EtronTech
EM68916CWQA
Figure 44. Precharge/precharge-all command to power-down entry
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
PR or PRA
CMD
CKE
CKE can go to LOW one clock after a Precharge or Precharge all command
tIS
Figure 45. MRS/EMRS command to power-down entry
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
MRS or
EMRS
CMD
CKE
tMRD
tIS
Figure 46. Asynchronous CKE LOW event
Stable clocks
tCK
CK#
CK
CKE
tDelay
tIS
CKE asynchronously drops LOW
Clocks can be turned off after this point
Figure 47. Clock frequency change in precharge power down mode
T0
T1
T2
T4
Tx
Tx+1
Ty
Ty+1
Ty+2
Ty+3
Ty+4
Tz
CK#
CK
DLL
RESET
CMD
CKE
ODT
NOP
NOP
NOP
NOP
NOP
Valid
Frequency Change Occurs here
200 Clocks
tIS
tIS
tXP
tRP
tAOFD
tIH
ODT is off during DLL RESET
Minimum 2 clocks required before
changing frequency
Stable new clock before power
down exit
Etron Confidential
58
Rev. 1.1
Apr. 2009
ETRON [ ETRON TECHNOLOGY, INC. ]
