SN54ALS646, SN54ALS648, SN54AS646

SN74ALS646A, SN74ALS648A, SN74AS646, SN74AS648

OCTAL BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS

SDAS039F – DECEMBER 1983 – REVISED JANUARY 1995

14

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

switching characteristics (see Figure 2)

PARAMETER

FROM

(INPUT)

TO

(OUTPUT)

VCC = 4.5 V to 5.5 V,

CL = 50 pF,

R1 = 500

Ω,

R2 = 500

Ω,

TA = MIN to MAX†

UNIT

SN54AS646

SN74AS646

MIN

MAX

MIN

MAX

fmax*

75

90

MHz

tPLH

CLKBA or CLKAB

AorB

2

9.5

2

8.5

ns

tPHL

CLKBA or CLKAB

A or B

2

10

2

9

ns

tPLH

AorB

BorA

2

11.5

2

9

ns

tPHL

A or B

B or A

1

8

1

7

ns

tPLH

SBA or SAB‡

AorB

2

13.5

2

11

ns

tPHL

SBA or SAB‡

A or B

2

11

2

9

ns

tPZH

OE

AorB

2

11

2

9

ns

tPZL

OE

A or B

3

15

3

14

ns

tPHZ

OE

AorB

2

11

2

9

ns

tPLZ

OE

A or B

2

11

2

9

ns

tPZH

DIR

AorB

3

21

3

16

ns

tPZL

DIR

A or B

3

24

3

18

ns

tPHZ

DIR

AorB

2

12

2

10

ns

tPLZ

DIR

A or B

2

12

2

10

ns

* On products compliant to MIL-STD-883, Class B, this parameter is based on characterization data but is not production tested.

† For conditions shown MIN or MAX, use the appropriate value specified under recommended operating conditions.

‡ These parameters are measured with the internal output state of the storage register opposite that of the bus input.