IS42S16400F
IC42S16400F
GENERAL DESCRIPTION
Theꢀ 64Mbꢀ SDRAMꢀ isꢀ aꢀ highꢀ speedꢀ CMOS,ꢀ dynamicꢀ
random-accessꢀ memoryꢀ designedꢀ toꢀ operateꢀ inꢀ 3.3Vꢀ
memoryꢀsystemsꢀcontainingꢀ67,108,864ꢀbits.ꢀꢀInternallyꢀ
configuredꢀasꢀaꢀquad-bankꢀDRAMꢀwithꢀaꢀsynchronousꢀ
interface.ꢀꢀEachꢀ16,777,216-bitꢀbankꢀisꢀorganizedꢀasꢀ4,096ꢀ
rows by 256 columns by 16 bits.
otherthreebankswillhidetheprechargecyclesandprovide
seamless, high-speed, random-access operation.
SDRAM readandwriteaccessesareburstorientedstarting
at a selected location and continuing for a programmed
numberꢀ ofꢀ locationsꢀ inꢀ aꢀ programmedꢀ sequence.ꢀ ꢀTheꢀ
registrationꢀ ofꢀ anꢀ ACTIVEꢀ commandꢀ beginsꢀ accesses,ꢀ
followedꢀbyꢀaꢀREADꢀorꢀWRITEꢀcommand.ꢀTheꢀACTIVEꢀ
command in conjunction with address bits registered are
usedꢀtoꢀselectꢀtheꢀbankꢀandꢀrowꢀtoꢀbeꢀaccessedꢀ(BA0,ꢀ
BA1ꢀselectꢀtheꢀbank;ꢀA0-A11ꢀselectꢀtheꢀrow).ꢀꢀTheꢀREADꢀ
orꢀWRITEꢀ commandsꢀ inꢀ conjunctionꢀ withꢀ addressꢀ bitsꢀ
registered are used to select the starting column location
for the burst access.
Theꢀ64MbꢀSDRAMꢀincludesꢀanꢀAUTOꢀREFRESHꢀMODE,ꢀ
and a power-saving, power-down mode. All signals are
registeredꢀonꢀtheꢀpositiveꢀedgeꢀofꢀtheꢀclockꢀsignal,ꢀCLK.ꢀ
AllꢀinputsꢀandꢀoutputsꢀareꢀLVTTLꢀcompatible.
Theꢀ64MbꢀSDRAMꢀhasꢀtheꢀabilityꢀtoꢀsynchronouslyꢀburstꢀ
data at a high data rate with automatic column-address
generation, theabilitytointerleavebetweeninternalbanks
to hide precharge time and the capability to randomly
change column addresses on each clock cycle during
burst access.
ProgrammableꢀREADꢀorꢀWRITEꢀburstꢀlengthsꢀconsistꢀofꢀ
1, 2, 4 and 8 locations, or full page, with a burst terminate
option.
A self-timed row precharge initiated at the end of the burst
sequenceꢀisꢀavailableꢀwithꢀtheꢀAUTOꢀPRECHARGEꢀfunctionꢀ
enabled. Precharge one bank while accessing one of the
FUNCTIONAL BLOCK DIAGRAM
CLK
CKE
CS
RAS
CAS
WE
DQM
DATA IN
BUFFER
COMMAND
DECODER
&
CLOCK
GENERATOR
16
16
REFRESH
CONTROLLER
MODE
REGISTER
DQ 0-15
A10
12
V
DD/VDDQ
SELF
DATA OUT
BUFFER
REFRESH
GND/GNDQ
A11
CONTROLLER
16
16
A9
A8
A7
A6
REFRESH
COUNTER
A5
A4
4096
A3
A2
A1
A0
BA0
BA1
4096
MEMORY CELL
ARRAY
4096
4096
12
BANK 0
ROW
ADDRESS
LATCH
ROW
ADDRESS
BUFFER
12
12
SENSE AMP I/O GATE
256K
(x 16)
COLUMN
ADDRESS LATCH
BANK CONTROL LOGIC
8
BURST COUNTER
COLUMN DECODER
COLUMN
ADDRESS BUFFER
8
2
Integrated Silicon Solution, Inc. — www.issi.com
Rev. A
03/19/08
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
