128K x 36, 256K x 18
IDT71V2556S
IDT71V2558S
IDT71V2556SA
IDT71V2558SA
3.3V Synchronous ZBT™ SRAMs
2.5V I/O, Burst Counter
Pipelined Outputs
Features
cycle,andtwocycleslatertheassociateddatacycleoccurs,beitread
or write.
The IDT71V2556/58 contain data I/O, address and control signal
registers.Outputenableistheonlyasynchronoussignalandcanbeused
todisabletheoutputsatanygiventime.
AClockEnable(CEN)pinallowsoperationoftheIDT71V2556/58to
besuspendedaslongasnecessary.Allsynchronousinputsareignored
when(CEN)ishighandtheinternaldeviceregisterswillholdtheirprevious
values.
Therearethreechipenablepins(CE1,CE2,CE2)thatallowtheuser
to deselect the device when desired. If any one of these three are not
assertedwhenADV/LDislow,nonewmemoryoperationcanbeinitiated.
However,anypendingdatatransfers(readsorwrites)willbecompleted.
Thedatabuswilltri-statetwocyclesafterchipisdeselectedorawriteis
initiated.
TheIDT71V2556/58hasanon-chipburstcounter.Intheburstmode,
theIDT71V2556/58canprovidefourcyclesofdataforasingleaddress
presentedtotheSRAM.Theorderoftheburstsequenceisdefinedbythe
LBOinputpin.TheLBOpinselectsbetweenlinearandinterleavedburst
sequence. The ADV/LD signal is used to load a new external address
(ADV/LD = LOW) or increment the internal burst counter (ADV/LD =
HIGH).
The IDT71V2556/58 SRAMs utilize IDT's latest high-performance
CMOSprocessandarepackagedinaJEDECstandard14mmx20mm
100-pinthinplasticquadflatpack(TQFP)aswellasa119ballgridarray
(BGA) and a 165 fine pitch ball grid array (fBGA).
◆
128K x 36, 256K x 18 memory configurations
◆
Supports high performance system speed - 200 MHz
(3.2 ns Clock-to-Data Access)
ZBTTM Feature - No dead cycles between write and read
◆
cycles
◆
Internally synchronized output buffer enable eliminates the
need to control OE
◆
Single R/W (READ/WRITE) control pin
◆
Positive clock-edge triggered address, data, and control
signal registers for fully pipelined applications
4-word burst capability (interleaved or linear)
Individual byte write (BW1 - BW4) control (May tie active)
Three chip enables for simple depth expansion
3.3V power supply (±5%), 2.5V I/O Supply (VDDQ)
Optional - Boundary Scan JTAG Interface (IEEE 1149.1
◆
◆
◆
◆
◆
complaint)
◆
Packaged in a JEDEC standard 100-pin plastic thin quad
flatpack (TQFP), 119 ball grid array (BGA) and 165 fine pitch
ball grid array (fBGA)
Description
TheIDT71V2556/58 are3.3Vhigh-speed4,718,592-bit(4.5Mega-
bit)synchronousSRAMS.Theyaredesignedtoeliminatedeadbuscycles
when turning the bus around between reads and writes, or writes and
TM
reads. Thus, they have been given the name ZBT , or Zero Bus
Turnaround.
AddressandcontrolsignalsareappliedtotheSRAMduringoneclock
PinDescriptionSummary
0
17
A -A
Address Inputs
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Output
Input
Input
I/O
Synchronous
Synchronous
Asynchronous
Synchronous
Synchronous
Synchronous
N/A
Chip Enables
1
2
2
CE , CE , CE
Output Enable
OE
R/W
CEN
Read/Write Signal
Clock Enable
Individual Byte Write Selects
Clock
1
2
3
4
BW , BW , BW , BW
CLK
ADV/LD
LBO
Advance burst address / Load new address
Linear / Interleaved Burst Order
Test Mode Select
Test Data Input
Synchronous
Static
TMS
TDI
Synchronous
Synchronous
N/A
TCK
TDO
TRST
ZZ
Te s t Clo c k
Te s t Data Outp ut
Synchronous
Asynchronous
Synchronous
Synchronous
Static
JTAG Reset (Optional)
Sleep Mode
0
31
P1
P4
I/O -I/O , I/O -I/O
Data Input / Output
Core Power, I/O Power
Ground
DD DDQ
V
, V
Supply
Supply
SS
V
Static
4875 tbl 01
OCTOBER 2004
1
©2004IntegratedDeviceTechnology,Inc.
DSC-4875/08