CD74FCT652

BiCMOS OCTAL BUS TRANSCEIVER AND REGISTER

WITH 3-STATE OUTPUTS

SCBS734A – JULY 2000 – REVISED JULY 2000

1

POST OFFICE BOX 655303

Power

and Circuit Design

Small-Outline (M) Package and Standard

Plastic (EN) DIP

description

The CD74FCT652 is an octal bus transceiver and resistor with 3-state outputs. It consists of D-type flip-flops

and control circuitry, arranged for multiplexed transmission of data directly from the data bus or from the internal

storage registers. Output-enable (OEAB and OEBA) inputs control the transceiver functions. The select-control

(SAB and SBA) inputs select real-time-data or stored-data transfer. A low-input level selects real-time data, and

a high-input level selects stored data. The select-control circuitry eliminates the typical decoding glitch that

occurs in a multiplexer during the transition between stored data and real-time data.

The device uses a small-geometry BiCMOS technology. The output stage is a combination of bipolar and CMOS

bounce and ground bounce and their effects during simultaneous output switching. The output configuration

also enhances switching speed and is capable of sinking 64 mA.

Data on the A or B data bus, or both, can be stored in the internal D-type flip-flop by low-to-high transitions at

the appropriate clock terminal (CLKAB and CLKBA), regardless of the state of the select or enable control

terminals. When SAB and SBA are in the real-time-transfer mode, it also is possible to store data without using

the internal D-type flip-flop by simultaneously enabling OEAB and OEBA. In this configuration, each output

reinforces its input. Thus, when all other data sources to the two sets of bus lines are at high impedance, each

set of bus lines remains at its last state.

pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver

(B to A). OEAB should be tied to GND through a pulldown resistor; the minimum value of the resistor is

determined by the current-sourcing capability of the driver (A to B).

The CD74FCT652 is characterized for operation from 0

°C to 70°C.

Copyright

© 2000, 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.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

EN OR M PACKAGE

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CLKAB

SAB

OEAB

A1

A2

A3

A4

A5

A6

A7

A8

GND

CLKBA

SBA

OEBA

B1

B2

B3

B4

B5

B6

B7

B8