SN54LVC646A, SN74LVC646A

OCTAL BUS TRANSCEIVERS AND REGISTERS

WITH 3-STATE OUTPUTS

SCAS302G – JANUARY 1993 – REVISED JUNE1998

2

POST OFFICE BOX 655303

description (continued)

Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of these devices as translators

in a mixed 3.3-V/5-V system environment.

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

The SN54LVC646A is characterized for operation over the full military temperature range of –55

°C to 125°C.

The SN74LVC646A is characterized for operation from –40

°C to 85°C.

FUNCTION TABLE

INPUTS

DATA I/O

OPERATION OR FUNCTION

OE

DIR

CLKAB

CLKBA

SAB

SBA

A1–A8

B1–B8

OPERATION OR FUNCTION

X

X

↑

X

X

X

Input

Unspecified†

Store A, B unspecified†

X

XX

↑

X

X

Unspecified†

Input

Store B, A unspecified†

H

X

↑

↑

X

X

Input

Input

Store A and B data

H

X

H or L

H or L

X

X

Input disabled

Input disabled

Isolation, hold storage

L

L

X

X

X

L

Output

Input

Real-time B data to A bus

L

L

X

H or L

X

H

Output

Input

Stored B data to A bus

L

H

X

X

L

X

Input

Output

Real-time A data to B bus

L

H

H or L

X

H

X

Input

Output

Stored A data to B bus

† The data-output functions can be enabled or disabled by various signals at OE and DIR. Data-input functions always are enabled; i.e., data at

the bus terminals is stored on every low-to-high transition of the clock inputs.