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72421 - Block Diagram


64 x 9 SyncFIFO, 5.0V

The 72421SyncFIFO™ is a 64 x 9 First-In, First-Out memory with clocked read and write controls. This FIFO is useful for a wide variety of data buffering needs such as graphics, local area networks and interprocessor communication. These FIFOs have 9-bit input and output ports. The Read Clock can be tied to the Write Clock for single clock operation or the two clocks can run asynchronous of one another for dual-clock operation.


  • 10 ns read/write cycle time
  • Read and Write Clocks can be independent
  • Dual-Ported zero fall-through time architecture
  • Empty and Full Flags signal FIFO status
  • Programmable Almost-Empty and Almost-Full flags can be set to any depth
  • Programmable Almost-Empty and Almost-Full flags default to Empty+7, and Full-7, respectively
  • Output enable puts output data bus in high-impedance state
  • Available in 32-pin PLCC and 32-pin TQFP packages
  • Industrial temperature range (–40C to +85C) is available

Product Specification

Core Voltage (V)Bus Width (bits)Density (Kb)Pkg. CodeInterfaceI/O TypeI/O Frequency (MHz)Cycle Time (ns)OrganizationTemp. RangeArchitectureAccess Time (ns)
591PL32, PR32Synchronous5.0 V TTL40.00, 66.00, 100.0064 x 9-40 to 85°C, 0 to 70°CUni-directional

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
72421L10JActivePL32PLCC32CNoTubeCheck Availability
72421L10J8ActivePL32PLCC32CNoReelCheck Availability
72421L10PFActivePR32TQFP32CNoTrayCheck Availability
72421L10PF8ActivePR32TQFP32CNoReelCheck Availability
72421L15JActivePL32PLCC32CNoTubeCheck Availability
72421L15J8ActivePL32PLCC32CNoReelCheck Availability
72421L15JIActivePL32PLCC32INoTubeCheck Availability
72421L15JI8ActivePL32PLCC32INoReelCheck Availability
72421L15PFActivePR32TQFP32CNoTrayCheck Availability
72421L15PF8ActivePR32TQFP32CNoReelCheck Availability
72421L15PFINot Recommended
PR32TQFP32INoTrayCheck Availability
72421L15PFI8Not Recommended
PR32TQFP32INoReelCheck Availability
72421L25JActivePL32PLCC32CNoTubeCheck Availability
72421L25J8ActivePL32PLCC32CNoReelCheck Availability
72421L25JIActivePL32PLCC32INoTubeCheck Availability
72421L25JI8ActivePL32PLCC32INoReelCheck Availability
72421L25PFActivePR32TQFP32CNoTrayCheck Availability
72421L25PF8ActivePR32TQFP32CNoReelCheck Availability
72421L25PFIActivePR32TQFP32INoTrayCheck Availability
72421L25PFI8ActivePR32TQFP32INoReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
72421-72251 Datasheet Datasheet PDF 286 KB Aug 8, 2013
Apps Notes & White Papers
AN-83: Width Expansion of SyncFIFOs Application Note PDF 73 KB Jul 31, 2006
AN-69:Depth Expansion of IDT's Sync FIFOs . . . Application Note PDF 112 KB Jul 30, 2002
PCN# : TB1303-01 Change of Carrier Tape for TQFP-32, TQFP-48 Product Change Notice PDF 472 KB Mar 31, 2013
PCN#: A-0410-02, Change IDT marking logo with new IDT gridless w Product Change Notice PDF 24 KB Nov 14, 2012
PCN# : A-0610-02 ASAT China as Alternate Facility for CABGA/CVBGA/FPBGA/TQFP/PQFP Product Change Notice PDF 252 KB Oct 19, 2006
show all (19)
PCN# A-0607-06 MMT Thailand as Alternate Assembly Facility for PLCC, SOIC 150mil/300mil Product Change Notice PDF 223 KB Oct 6, 2006
A-0603-04 Transfer TQFP and PQFP from ASAT HK to ASAT China Product Change Notice PDF 164 KB May 10, 2006
PCN#: TB-0512-01 Reel Color Changed from Blue to Black Product Change Notice PDF 729 KB Dec 16, 2005
PCN# A-0504-02R2: Assembly Transfer IDT-Manila to OSE-Ph Product Change Notice PDF 38 KB Aug 4, 2005
PCN#A-0504-02R1: Assembly Transfer IDT-Manila to OSE-Ph Product Change Notice PDF 16 KB Jul 22, 2005
PCN#: A-0504-02, Transfer assembly facility IDT-Manila to OSE-Ph Product Change Notice PDF 47 KB Apr 29, 2005
PCN#: A-0412-04 - To comply with Pb-free labels - Green Products Product Change Notice PDF 80 KB Dec 14, 2004
PCN#: A-0310-01, Green Products Product Change Notice PDF 26 KB Oct 10, 2003
PCN#: A-0309-04, new mold compound G600 material Product Change Notice PDF 134 KB Oct 7, 2003
PCN#: G-0302-06, New die attach 3230 from Ablestik Product Change Notice PDF 150 KB Mar 20, 2003
PCN# F0206-07R1: Wafer Fabrication Site Change Product Change Notice PDF 65 KB Sep 17, 2002
PCN# G-0206-08, Orientation of square PQFP & TQFP Product Change Notice PDF 150 KB Jun 17, 2002
PCN# G-0203-05 Mold Compound Product Change Notice PDF 40 KB Apr 16, 2002
PCN# G0106-01, Moisture Sensitive Label Change Product Change Notice PDF 274 KB Jun 11, 2001
PDN for selected Military grade FIFO products Product Delete Notice PDF 45 KB Feb 5, 2001
PCN# G9911-05, To qualify low alpha mold compound. Product Change Notice PDF 44 KB Nov 18, 1999

Software & Tools

Title Type Format File Size Datesort icon
72421 IBIS Model - IBIS ZIP 10 KB Jan 22, 1999