74AC257 datasheet(5/11 Pages) STMICROELECTRONICS

5 / 11 page

74AC257

5/11

AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = tf = 3ns)

(*) Voltage range is 3.3V

± 0.3V

(**) Voltage range is 5.0V

± 0.5V

CAPACITIVE CHARACTERISTICS

1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without

load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. ICC(opr) = CPD x VCC x fIN + ICC/4 (per circuit)

Symbol

Parameter

Test Condition

Value

Unit

VCC

(V)

TA = 25°C

-40 to 85°C

-55 to 125°C

Min.

Typ.

Max.

Min.

Max.

Min.

Max.

tPLH tPHL Propagation Delay

Time

A, B to Y

3.3(*)

1.5

5.5

8.5

1.5

9.0

1.5

9.0

5.0(**)

1.5

4.5

6.0

1.5

7.0

1.5

7.0

tPLH tPHL Propagation Delay

Time

SELECT to Y

3.3(*)

1.5

7.0

10.5

1.5

11.5

1.5

11.5

5.0(**)

1.5

5.5

7.5

1.5

8.5

1.5

8.5

tPZL tPZH Output Enable

Time

3.3(*)

1.5

5.5

9.0

1.5

100

1.5

100

5.0(**)

1.5

4.5

7.5

1.5

8.5

1.5

8.5

tPLZ tPHZ Output Disable

Time

3.3(*)

1.5

7.0

10.0

1.5

11.0

1.5

13.0

5.0(**)

1.5

5.5

9.0

1.5

10.0

1.5

11.0

Symbol

Parameter

Test Condition

Value

Unit

VCC

(V)

TA = 25°C

-40 to 85°C

-55 to 125°C

Min.

Typ.

Max.

Min.

Max.

Min.

Max.

CIN

Input Capacitance

5.0

COUT

Output

Capacitance

5.0

CPD

Power Dissipation

Capacitance (note

5.0

fIN = 10MHz

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