K522H1HACF-B050 Datasheet, PDF (78/94 Pages) Samsung semiconductor – MCP Specification

K522H1HACF-B050
datasheet
Rev. 1.0
MCP Memory
18. AUTO REFRESH & SELF REFRESH
18.1. Auto Refresh
An auto refresh command is issued by having CS, RAS and CAS held low with CKE and WE high at the rising edge of the clock(CK). All banks must be
precharged and idle for tRP(min) before the auto refresh command is applied. Once this cycle has been started, no control of the external address pins
are required because of the internal address counter. When the refresh cycle has completed, all banks will be in the idle state. A delay between the auto
refresh command and the next activate command or subsequent auto refresh command must be greater than or equal to the tRFC(min).
CK
CK
Command PRE
CKE = High
NOP
NOP
Auto
Refresh
NOP
NOP
NOP
tRP
tRFC(min)
DQ
DQS
High-Z
High-Z
ACT
NOP
NOP
Figure 14. Auto refresh timing
NOTE :
1) tRP=3CLK
2) Device must be in the all banks idle state prior to entering Auto refresh mode.
18.2. Self Refresh
A Self Refresh command is defined by having CS, RAS, CAS and CKE held low with WE high at the rising edge of the clock. Once the self Refresh com-
mand is initiated, CKE must be held low to keep the device in Self Refresh mode. After 1 clock cycle from the self refresh command, all of the external
control signals including system clock(CK, CK) can be disabled except CKE. The clock is internally disabled during Self Refresh operation to reduce
power. Before returning CKE high to exit the Self Refresh mode, apply stable clock input signal with Deselect or NOP command asserted.
CK
CK
Command NOP
Self
Refresh
CKE
tIS
DQ
DQS
tRFC
Stable Clock
NOP
NOP
tIS
High-Z
High-Z
Figure 15. Self refresh timing
NOTE :
1) Device must be in the all banks idle state prior to entering Self Refresh mode.
2) The minimum time that the device must remain in Self Refresh mode is tRFC.
NOP
NOP
tXSR(min)
Active
NOP
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