3.3 VOLT CMOS SyncFIFOTM
512 x 36
1,024 x 36
72V3631
72V3641
• Available in space-saving 120-pin thin quad flat package (TQFP)
• Pin and functionally compatible versions of the 5V operating
723631/723641
• Easily expandable in width and depth
• Green parts are available, see ordering information
FEATURES
• Storage capacity:
72V3631 - 512 x 36
72V3641 - 1,024 x 36
• Supports clock frequencies up to 67 MHz
• Fast access times of 10ns
DESCRIPTION
• Free-running CLKA and CLKB can be asynchronous or coinci-
dent (permits simultaneous reading and writing of data on a
single clock edge)
• Clocked FIFO buffering data from Port A to Port B
• Synchronous read retransmit capability
• Mailbox register in each direction
• Programmable Almost-Full and Almost-Empty flags
• Microprocessor interface control logic
• Input Ready (IR) and Almost-Full (AF) flags synchronized by
CLKA
• Output Ready (OR) and Almost-Empty (AE) flags synchronized
by CLKB
The72V3631/72V3641arepinandfunctionallycompatibleversonsofthe
723631/723641,designedtorunoffa3.3Vsupplyforexceptionallylow-power
consumption. Thesedevicesaremonolithichigh-speed,low-power,CMOS
clockedFIFOmemory. Itsupportsclockfrequenciesupto67MHzandhasread
accesstimesasfastas10ns. The512/1,024x36dual-portSRAMFIFObuffers
datafromportAtoPortB. TheFIFOmemoryhasretransmitcapability,which
allowspreviouslyreaddatatobeaccessedagain. TheFIFOoperatesinFirst
WordFallThroughmodeandhasflagstoindicateemptyandfullconditionsand
conditions and two programmable flags (Almost-Full and Almost-Empty) to
indicatewhenaselectednumberofwordsisstoredinmemory. Communication
FUNCTIONAL BLOCK DIAGRAM
MBF1
Mail 1
Register
CLKA
CSA
W/RA
ENA
MBA
Port-A
Control
Logic
RAM ARRAY
512 x 36
1,024 x 36
Reset
Logic
RST
RTM
36
Read
Pointer
Write
Pointer
RFM
A0 - A35
B0 - B35
Status Flag
OR
AE
IR
AF
Logic
Flag Offset
Registers
FS0/SD
FS1/SE
N
10
CLKB
CSB
W/RB
ENB
MBB
Port-B
Control
Logic
Mail 2
Register
4658 drw 01
MBF2
COMMERCIAL TEMPERATURE RANGE
1
1
Oct.29.21