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72805 - Block Diagram


256 x 18 DualSync FIFO, 5.0V

The 72805 is a 256 x 18 First-In, First-Out memory with clocked read and write controls. It is functionally equivalent to two 72205 FIFOs in a single package with all associated control, data, and flag lines assigned to independent pins and would be applicable for a wide variety of data buffering needs, such as optical disk controllers, Local Area Networks (LANs), and interprocessor communication. Each of the two FIFOs has an 18-bit input and output port. 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.


  • Ideal for the following applications:
  • Network switching
  • Two level prioritization of parallel data
  • Bidirectional data transfer
  • Bus
  • matching between 18
  • bit and 36
  • bit data paths
  • Width expansion to 36
  • bit per package
  • Depth expansion to 8,192 words per package
  • 10ns read/write cycle time, 6.5ns access time
  • IDT Standard or First Word Fall Through timing
  • Single or double register buffered Empty and Full Flags
  • Easily expandable in depth and width
  • Asynchronous or coincident Read and Write clocks
  • Async or sync programmable Almost Empty and Almost Full flags with default settings
  • Half
  • Full flag capability
  • Available in 128-pin TQFP and 121 PBGA 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)
5184BG121, PK128, PKG128Synchronous5.0 V TTL40.00, 66.00, 100.00256 x 18-40 to 85°C, 0 to 70°CDual FIFO

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
72805LB10PFActivePK128TQFP128CNoTrayCheck Availability
72805LB10PF8ActivePK128TQFP128CNoReelCheck Availability
72805LB15BGNot Recommended
BG121PBGA121CNoTrayCheck Availability
72805LB15BG8Not Recommended
BG121PBGA121CNoReelCheck Availability
72805LB15PFActivePK128TQFP128CNoTrayCheck Availability
72805LB15PF8ActivePK128TQFP128CNoReelCheck Availability
72805LB15PFIPreviewPK128TQFP128INoTrayCheck Availability
72805LB15PFI8PreviewPK128TQFP128INoReelCheck Availability
72805LB25BGNot Recommended
BG121PBGA121CNoTrayCheck Availability
72805LB25BG8Not Recommended
BG121PBGA121CNoReelCheck Availability
72805LB25PFActivePK128TQFP128CNoTrayCheck Availability
72805LB25PF8ActivePK128TQFP128CNoReelCheck Availability
72805LB10PFGActivePKG128TQFP128CYesTrayCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
72805-72845 Datasheet Datasheet PDF 259 KB May 23, 2016
PCN# : A1606-02 Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 567 KB Aug 26, 2016
PCN#: A-0410-02, Change IDT marking logo with new IDT gridless w Product Change Notice PDF 24 KB Nov 14, 2012
A-0603-04 Transfer TQFP and PQFP from ASAT HK to ASAT China Product Change Notice PDF 164 KB May 10, 2006
show all (18)
PCN#: TB-0512-01 Reel Color Changed from Blue to Black Product Change Notice PDF 729 KB Dec 16, 2005
PCN A-0506-03; Packing Material Change Product Change Notice PDF 290 KB Jul 19, 2005
PCN#: A-0412-04 - To comply with Pb-free labels - Green Products Product Change Notice PDF 80 KB Dec 14, 2004
PCN#: A-0403-03, BGA package family Product Change Notice PDF 38 KB Dec 9, 2004
PCN#: A-0309-05, new m/c-G770 & d/a-2300 material Product Change Notice PDF 211 KB Oct 16, 2003
PCN#: A-0310-01, Green Products Product Change Notice PDF 26 KB Oct 10, 2003
PCN#G-0302-05, New mold compound EME-G700 series Product Change Notice PDF 65 KB Mar 20, 2003
PCN#: G-0302-06, New die attach 3230 from Ablestik Product Change Notice PDF 150 KB Mar 20, 2003
PCN# F0202-04R1: Wafer Fabrication Site Change Product Change Notice PDF 50 KB Jun 1, 2002
PCN# G-0110-06 REV.1 Mold Compound Product Change Notice PDF 48 KB Apr 26, 2002
PCN# F-0203-04: Auto Mold Process Product Change Notice PDF 37 KB Mar 19, 2002
PCN# G-0110-06 Mold Compound Product Change Notice PDF 47 KB Dec 14, 2001
PCN# G0106-01, Moisture Sensitive Label Change Product Change Notice PDF 274 KB Jun 11, 2001
PCN# G0003-03, Shipping changed (tray to tube) Product Change Notice PDF 20 KB Mar 20, 2000
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
72805 HSPICE Model - HSPICE application/x-tar 32 KB Jun 29, 1999
72805 IBIS Model - IBIS ZIP 11 KB Jan 22, 1999