Philips Semiconductors

Product specification

74LVT646

3.3V Octal bus transceiver/register (3-State)

1998 Feb 19

4

REAL TIME BUS TRANSFER

BUS B TO BUS A

OE

DIR CPAB CPBA SAB

SBA

LL

X

X

X

L

REAL TIME BUS TRANSFER

BUS A TO BUS B

OE

DIR CPAB CPBA SAB

SBA

LH

X

X

L

X

STORAGE FROM

A, B, OR A AND B

OE

DIR CPAB CPBA SAB

SBA

LH

↑

XXX

LL

X

↑

XX

HX

↑↑

XX

TRANSFER STORED DATA

TO A OR B

OE

DIR CPAB CPBA SAB

SBA

L

L

X

H or L

X

H

L

H

H or L

X

H

X

A

A

A

A

B

B

B

B

SV00049

FUNCTION TABLE

INPUTS

DATA I/O

OPERATING MODE

OE

DIR

CPAB

CPBA

SAB

SBA

An

Bn

OPERATING MODE

X

X

↑

X

X

X

Input

Unspecified

output*

Store A, B unspecified

X

X

X

↑

X

X

Unspecified

output*

Input

Store B, A unspecified

H

H

X

X

↑

H or L

↑

H or L

X

X

X

X

Input

Input

Store A and B data

Isolation, hold storage

L

L

L

L

X

X

X

H or L

X

X

L

H

Output

Input

Real time B data to A bus

Stored B data to A bus

L

L

H

H

X

H or L

X

X

L

H

X

X

Input

Output

Real time A data to B bus

Stored A data to B bus

H = High voltage level

L

= Low voltage level

X = Don’t care

↑ = Low-to-High clock transition

*

The data output function may be enabled or disabled by various signals at the OE input. Data input functions are always enabled, i.e.,

data at the bus pins will be stored on every Low-to-High transition of the clock.