MILITARYANDINDUSTRIALTEMPERATURERANGES

IDT54/74FCT646T/AT/CT

FASTCMOSOCTALTRANSCEIVER/REGISTER(3-STATE)

1

JUNE 2002

MILITARY AND INDUSTRIAL TEMPERATURE RANGES

The IDT logo is a registered trademark of Integrated Device Technology, Inc.

© 2002 Integrated Device Technology, Inc.

DSC-5505/3

FEATURES:

• Std., A, and C grades

• Low input and output leakage

≤≤≤≤≤1µA (max.)

• CMOS power levels

• True TTL input and output compatibility:

• Meets or exceeds JEDEC standard 18 specifications

• Military product compliant to MIL-STD-883, Class B and DESC

listed (dual marked)

• Power off disable outputs permit "live insertion"

• Available in the following packages:

– Industrial: SOIC, SSOP, QSOP, TSSOP

– Military: CERDIP, LCC

FUNCTIONAL BLOCK DIAGRAM

IDT54/74FCT646T/AT/CT

FAST CMOS OCTAL

TRANSCEIVER/

REGISTER (3-STATE)

DESCRIPTION:

The FCT646T consists of a bus transceiver with 3-state D-type flip-flops

and control circuitry arranged for multiplexed transmission of data directly

from the data bus or from the internal storage registers. The FCT646T

utilizes the enable control (G) and direction (DIR) pins to control the

transceiver functions.

SABandSBAcontrolpinsareprovidedtoselecteitherreal-timeorstored

data transfer. The circuitry used for select control will eliminate the typical

decoding glitch that occurs in a multiplexer during the transition between

stored and real-time data. A low input level selects real-time data and a high

selects stored data.

Data on the A or B data bus, or both, can be stored in the internal D flip-

flops by low-to-high transitions at the appropriate clock pins (CPAB or

CPBA), regardless of the select or enable control pins.

A1

G

DIR

CPB A

SBA

CPA B

SAB

O NE OF EIG HT CHANNELS

B REG

A REG

B1

1D

C1

C1

1D

TO SEVE N O THER CHANN ELS