5-1

FACT DATA

Octal Transceiver/Register with

3State Outputs (Noninverting)

The MC74AC646/74ACT646 consist of registered bus transceiver circuits,

with outputs, D-type flip-flops and control circuitry providing multiplexed transmission

of data directly from the input bus or from the internal storage registers. Data on the

A or B bus will be loaded into the respective registers on the LOW-to-HIGH transition

of the appropriate clock pin (CAB or CBA). The four fundamental data handling

functions available are illustrated in the following figures.

REAL TIME TRANSFER

A-BUS TO B-BUS

REAL TIME TRANSFER

B-BUS TO A-BUS

REG

REG

REG

REG

REG

REG

REG

REG

B-BUS

B-BUS

A-BUS

A-BUS

B-BUS

B-BUS

A-BUS

A-BUS

STORAGE

FROM BUS TO REGISTER

TRANSFER

FROM REGISTER TO BUS

Figure 1

Figure 2

Figure 3

Figure 4

• Independent Registers for A and B Buses

• Multiplexed Real-Time and Stored Data Transfers

• Choice of True and Inverting Data Paths

• 3-State Outputs

• 300 mil Slim Dual In-Line Package

• Outputs Source/Sink 24 mA

• ′ACT646 Has TTL Compatible Inputs

MC74AC646

MC74ACT646

OCTAL

TRANSCEIVER/REGISTER

WITH 3-STATE OUTPUTS

(NON-INVERTING)

N SUFFIX

CASE 724-03

PLASTIC

DW SUFFIX

CASE 751E-04

SOIC PACKAGE

LOGIC SYMBOL

A0 A1 A2 A3 A4 A5 A6 A7

B0 B1 B2 B3 B4 B5 B6 B7

CAB

SAB

DIR

CBA

SBA

G