SN54ACT240, SN74ACT240

OCTAL BUFFERS/DRIVERS

WITH 3-STATE OUTPUTS

SCAS515C – JUNE 1995 – REVISED OCTOBER 2002

4

POST OFFICE BOX 655303

switching

characteristics

over

recommended

operating

free-air

temperature

range,

PARAMETER

FROM

TO

TA = 25°C

SN54ACT240

SN74ACT240

UNIT

PARAMETER

(INPUT)

(OUTPUT)

MIN

TYP

MAX

MIN

MAX

MIN

MAX

UNIT

tPLH

A

Y

1.5

6

8.5

1

9.5

1.5

9.5

ns

tPHL

A

Y

1.5

5.5

7.5

1

9

1.5

8.5

ns

tPZH

OE

Y

1.5

7

8.5

1

10

1

9.5

ns

tPZL

OE

Y

2

7

9.5

1

11.5

1.5

10.5

ns

tPHZ

OE

Y

2

8

9.5

1

11

2

10.5

ns

tPLZ

OE

Y

2.5

6.5

10

1

11.5

2

10.5

ns

PARAMETER

TEST CONDITIONS

TYP

UNIT

Cpd

Power dissipation capacitance per buffer/driver

CL = 50 pF,

f = 1 MHz

45

pF

PARAMETER MEASUREMENT INFORMATION

From Output

Under Test

CL = 50 pF

(see Note A)

LOAD CIRCUIT

S1

2

× VCC

500

Ω

500

Ω

tPLH

tPHL

Output

Control

(low-level

enabling)

Output

Waveform 1

S1 at 2

× VCC

(see Note B)

Output

Waveform 2

S1 at Open

(see Note B)

VOL

VOH

tPZL

tPZH

tPLZ

tPHZ

1.5 V

1.5 V

1.5 V

1.5 V

≈VCC

3 V

0 V

50% VCC

50% VCC

VOH

VOL

0 V

50% VCC

VOL + 0.3 V

50% VCC

≈0 V

3 V

Open

Input

Output

VOLTAGE WAVEFORMS

VOLTAGE WAVEFORMS

tPLH/tPHL

tPLZ/tPZL

tPHZ/tPZH

Open

2

× VCC

Open

TEST

S1

VOH – 0.3 V

NOTES: A. CL includes probe and jig capacitance.

B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.

Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.

C. All input pulses are supplied by generators having the following characteristics: PRR

≤ 1 MHz, ZO = 50 Ω, tr ≤ 2.5 ns, tf ≤ 2.5 ns.

D. The outputs are measured one at a time with one input transition per measurement.

Figure 1. Load Circuit and Voltage Waveforms