SN74ABT3613
64 × 36 CLOCKED FIRST-IN, FIRST-OUT MEMORY
WITH BUS MATCHING AND BYTE SWAPPING
SCBS128F – JULY 1992 – REVISED APRIL 1998
Low-Power Advanced BiCMOS Technology
Programmable Almost-Full and
Almost-Empty Flags
Free-Running CLKA and CLKB Can Be
Asynchronous or Coincident
Microprocessor Interface Control Logic
FF and AF Flags Synchronized by CLKA
EF and AE Flags Synchronized by CLKB
Passive Parity Checking on Each Port
64 × 36 FIFO Buffering Data From Port A to
Port B
Mailbox-Bypass Registers in Each
Direction
Parity Generation Can Be Selected for Each
Port
Dynamic Port-B Bus Sizing of 36 Bits (Long
Word), 18 Bits (Word), and 9 Bits (Byte)
Supports Clock Frequencies up to 67 MHz
Fast Access Times of 10 ns
Selection of Big- or Little-Endian Format for
Word and Byte Bus Sizes
Package Options Include 120-Pin Thin
Quad Flat (PCB) and 132-Pin Quad Flat
(PQ) Packages
Three Modes of Byte-Order Swapping on
Port B
description
The SN74ABT3613 is a high-speed, low-power BiCMOS clocked FIFO memory. It supports clock frequencies
up to 67 MHz and has read-access times as fast as 10 ns. A 64 × 36 dual-port SRAM FIFO in this device buffers
data from port A to port B. The FIFO has flags to indicate empty and full conditions and two programmable flags
(almost full and almost empty) to indicate when a selected number of words is stored in memory. FIFO data on
port B can be output in 36-bit, 18-bit, and 9-bit formats, with a choice of big- or little-endian configurations. Three
modes of byte-order swapping are possible with any bus-size selection. Communication between each port can
bypass the FIFO via two 36-bit mailbox registers. Each mailbox register has a flag to signal when new mail has
been stored. Parity is checked passively on each port and can be ignored if not desired. Parity generation can
be selected for data read from each port.
The SN74ABT3613 is a clocked FIFO, which means each port employs a synchronous interface. All data
transfersthroughaportaregatedtothelow-to-hightransitionofacontinuous(free-running)portclockbyenable
signals. The continuous clocks for each port are independent of one another and can be asynchronous or
coincident. The enables for each port are arranged to provide a simple interface between microprocessors
and/or buses controlled by a synchronous interface.
The full flag (FF) and almost-full (AF) flag of a FIFO are two-stage synchronized to the port clock that writes data
to its array. The empty flag (EF) and almost-empty (AE) flag of a FIFO are two-stage synchronized to the port
clock that reads data from its array.
The SN74ABT3613 is characterized for operation from 0°C to 70°C.
For more information on this device family, see the following application reports:
FIFO Mailbox-Bypass Registers: Using Bypass Registers to Initialize DMA Control
(literature number SCAA007)
Advanced Bus-Matching/Byte-Swapping Features for Internetworking FIFO Applications
(literature number SCAA014)
Parity-Generate and Parity-Check Features for High-Bandwidth-Computing FIFO Applications
(literature number SCAA015)
Internetworking the SN74ABT3614 (literature number SCAA018)
Metastability Performance of Clocked FIFOs (literature number SCZA004)
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 1998, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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