IS42S16400F
IC42S16400F
BURST TERMINATE
AUTOꢀPRECHARGEꢀdoesꢀnotꢀapplyꢀexceptꢀinꢀfull-pageꢀ
burstꢀ mode.ꢀ Uponꢀ completionꢀ ofꢀ theꢀ READꢀ orꢀWRITEꢀ
burst, a precharge of the bank/row that is addressed is
automatically performed.
TheꢀBURSTꢀTERMINATEꢀcommandꢀforciblyꢀterminatesꢀ
the burst read and write operations by truncating either
fixed-lengthꢀ orꢀ full-pageꢀ burstsꢀ andꢀ theꢀ mostꢀ recentlyꢀ
registeredꢀREADꢀorꢀWRITEꢀcommandꢀpriorꢀtoꢀtheꢀBURSTꢀ
TERMINATE.
AUTO REFRESH COMMAND
COMMAND INHIBIT
COMMANDꢀINHIBITꢀpreventsꢀnewꢀcommandsꢀfromꢀbeingꢀ
executed.ꢀOperationsꢀinꢀprogressꢀareꢀnotꢀaffected,ꢀapartꢀ
fromꢀwhetherꢀtheꢀCLKꢀsignalꢀisꢀenabled
ThisꢀcommandꢀexecutesꢀtheꢀAUTOꢀREFRESHꢀoperation.ꢀ
Theꢀrowꢀaddressꢀandꢀbankꢀtoꢀbeꢀrefreshedꢀareꢀautomaticallyꢀ
generatedꢀduringꢀthisꢀoperation.ꢀ Theꢀstipulatedꢀperiodꢀ(tr c )is
required for a single refresh operation, and no other com-
mandsꢀcanꢀbeꢀexecutedꢀduringꢀthisꢀperiod.ꢀ Thisꢀcommandꢀisꢀ
executedꢀatꢀleastꢀ4096ꢀtimesꢀeveryꢀ64ms.ꢀDuringꢀanꢀAUTOꢀ
REFRESHꢀcommand,ꢀaddressꢀbitsꢀareꢀ“Don’tꢀCare”.ꢀꢀThisꢀ
commandꢀcorrespondsꢀtoꢀCBRꢀAuto-refresh.
NO OPERATION
When CSꢀisꢀlow,ꢀtheꢀNOPꢀcommandꢀpreventsꢀunwantedꢀ
commands from being registered during idle or wait
states.
SELF REFRESH
LOAD MODE REGISTER
DuringꢀtheꢀSELFꢀREFRESHꢀoperation,ꢀtheꢀrowꢀaddressꢀtoꢀ
be refreshed, the bank, and the refresh interval are gen-
eratedꢀautomaticallyꢀinternally.ꢀꢀSELFꢀREFRESHꢀcanꢀbeꢀ
usedꢀtoꢀretainꢀdataꢀinꢀtheꢀSDRAMꢀwithoutꢀexternalꢀclocking,ꢀ
evenꢀifꢀtheꢀrestꢀofꢀtheꢀsystemꢀisꢀpoweredꢀdown.ꢀTheꢀSELFꢀ
REFRESHꢀoperationꢀisꢀstartedꢀbyꢀdroppingꢀtheꢀCKEꢀpinꢀ
fromꢀHIGHꢀtoꢀLOW.ꢀDuringꢀtheꢀSELFꢀREFRESHꢀoperationꢀ
allꢀotherꢀinputsꢀtoꢀtheꢀSDRAMꢀbecomeꢀ“Don’tꢀCare”.ꢀTheꢀ
device must remain in self refresh mode for a minimum
period equal to tr a s or may remain in self refresh mode
forꢀanꢀindefiniteꢀperiodꢀbeyondꢀthat.ꢀTheꢀSELF-REFRESHꢀ
operationꢀcontinuesꢀasꢀlongꢀasꢀtheꢀCKEꢀpinꢀremainsꢀLOWꢀ
andꢀthereꢀisꢀnoꢀneedꢀforꢀexternalꢀcontrolꢀofꢀanyꢀotherꢀpins.ꢀ
Theꢀnextꢀcommandꢀcannotꢀbeꢀexecutedꢀuntilꢀtheꢀdeviceꢀ
internal recovery period (tr c )ꢀ hasꢀ elapsed.ꢀ Onceꢀ CKEꢀ
goesꢀHIGH,ꢀtheꢀNOPꢀcommandꢀmustꢀbeꢀissuedꢀ(minimum
of two clocks) to provide time for the completion of any
internal refresh in progress. After the self-refresh, since it
is impossible to determine the address of the last row to
beꢀrefreshed,ꢀanꢀAUTO-REFRESHꢀshouldꢀimmediatelyꢀbeꢀ
performed for all addresses.
DuringꢀtheꢀLOADꢀMODEꢀREGISTERꢀcommandꢀtheꢀmodeꢀ
registerꢀisꢀloadedꢀfromꢀA0-A11.ꢀꢀThisꢀcommandꢀcanꢀonlyꢀ
be issued when all banks are idle.
ACTIVE COMMAND
Whenꢀ theꢀ ACTIVEꢀ COMMANDꢀ isꢀ activated,ꢀ BA0,ꢀ BA1ꢀ
inputs selects a bank to be accessed, and the address
inputsꢀonꢀA0-A11ꢀselectsꢀtheꢀrow.ꢀꢀꢀUntilꢀaꢀPRECHARGEꢀ
command is issued to the bank, the row remains open
for accesses.
Integrated Silicon Solution, Inc. — www.issi.com
5
Rev. A
03/19/08
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
