SN54HCT646, SN74HCT646

OCTAL BUS TRANSCEIVERS AND REGISTERS

WITH 3-STATE OUTPUTS

SCLS178C – MARCH 1984 – REVISED MARCH 2003

5

POST OFFICE BOX 655303

recommended operating conditions (see Note 4)

SN54HCT646

SN74HCT646

UNIT

MIN

NOM

MAX

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.5

5

5.5

4.5

5

5.5

V

VIH

High-level input voltage

VCC = 4.5 V to 5.5 V

2

2

V

VIL

Low-level input voltage

VCC = 4.5 V to 5.5 V

0.8

0.8

V

VI

Input voltage

0

VCC

0

VCC

V

VO

Output voltage

0

VCC

0

VCC

V

tt

Input transition (rise and fall) time

500

500

ns

TA

Operating free-air temperature

–55

125

–40

85

°C

NOTE 4: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,

Implications of Slow or Floating CMOS Inputs, literature number SCBA004.

electrical characteristics over recommended operating free-air temperature range (unless

otherwise noted)

PARAMETER

TEST CONDITIONS

VCC

TA = 25°C

SN54HCT646

SN74HCT646

UNIT

PARAMETER

TEST CONDITIONS

VCC

MIN

TYP

MAX

MIN

MAX

MIN

MAX

UNIT

VOH

VI =VIH or VIL

IOH = –20 µA

45 V

4.4

4.499

4.4

4.4

V

VOH

VI = VIH or VIL

IOH = –6 mA

4.5 V

3.98

4.3

3.7

3.84

V

VOL

VI =VIH or VIL

IOL = 20 µA

45 V

0.001

0.1

0.1

0.1

V

VOL

VI = VIH or VIL

IOL = 6 mA

4.5 V

0.17

0.26

0.4

0.33

V

II

Control inputs

VI = VCC or 0

5.5 V

±0.1

±100

±1000

±1000

nA

IOZ

A or B

VO = VCC or 0

5.5 V

±0.01

±0.5

±10

±5

µA

ICC

VI = VCC or 0,

IO = 0

5.5 V

8

160

80

µA

∆ICC†

One input at 0.5 V or 2.4 V,

Other inputs at 0 or VCC

5.5 V

1.4

2.4

3

2.9

mA

Ci

Control inputs

4.5 V

to 5.5 V

3

10

10

10

pF

† This is the increase in supply current for each input that is at one of the specified TTL voltage levels, rather than 0 V or VCC.

timing requirements over recommended operating free-air temperature range (unless otherwise

noted)

VCC

TA = 25°C

SN54HCT646

SN74HCT646

UNIT

VCC

MIN

MAX

MIN

MAX

MIN

MAX

UNIT

f lk

Clock frequency

4.5 V

31

22

27

MHz

fclock

Clock frequency

5.5 V

36

24

29

MHz

t

Pulse duration CLKBA or CLKAB high or low

4.5 V

16

23

19

ns

tw

Pulse duration, CLKBA or CLKAB high or low

5.5 V

14

21

17

ns

t

S t

ti

A b f

CLKAB

↑

B b f

CLKBA

↑

4.5 V

20

30

25

ns

tsu

Setup time, A before CLKAB

↑ or B before CLKBA↑

5.5 V

18

27

23

ns

th

Hold time A after CLKAB

↑ or B after CLKBA↑

4.5 V

5

5

5

ns

th

Hold time, A after CLKAB

↑ or B after CLKBA↑

5.5 V

5

5

5

ns

PRODUCT PREVIEW information concerns products in the formative or

design phase of development. Characteristic data and other

specifications are design goals. Texas Instruments reserves the right to

change or discontinue these products without notice.