SN54ABT646A, SN74ABT646A

OCTAL BUS TRANSCEIVERS AND REGISTERS

WITH 3STATE OUTPUTS

SCBS069H − JULY 1991 − REVISED MAY 2004

9

POST OFFICE BOX 655303

PARAMETER MEASUREMENT INFORMATION

1.5 V

th

tsu

From Output

Under Test

CL = 50 pF

(see Note A)

LOAD CIRCUIT

S1

7 V

Open

GND

500

Ω

500

Ω

Data Input

Timing Input

1.5 V

3 V

0 V

1.5 V

1.5 V

3 V

0 V

3 V

0 V

1.5 V

tw

Input

VOLTAGE WAVEFORMS

SETUP AND HOLD TIMES

VOLTAGE WAVEFORMS

PROPAGATION DELAY TIMES

INVERTING AND NONINVERTING OUTPUTS

VOLTAGE WAVEFORMS

PULSE DURATION

tPLH

tPHL

tPHL

tPLH

VOH

VOH

VOL

VOL

1.5 V

1.5 V

3 V

0 V

1.5 V

1.5 V

Input

1.5 V

Output

Control

Output

Waveform 1

S1 at 7 V

(see Note B)

Output

Waveform 2

S1 at Open

(see Note B)

VOL

VOH

tPZL

tPZH

tPLZ

tPHZ

1.5 V

1.5 V

3.5 V

0 V

1.5 V

VOL + 0.3 V

1.5 V

VOH − 0.3 V

≈0 V

3 V

VOLTAGE WAVEFORMS

ENABLE AND DISABLE TIMES

LOW- AND HIGH-LEVEL ENABLING

Output

Output

tPLH/tPHL

tPLZ/tPZL

tPHZ/tPZH

Open

7 V

Open

TEST

S1

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

≤ 10 MHz, ZO = 50 Ω, tr ≤ 2.5 ns, tf ≤ 2.5 ns.

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

E. All parameters and waveforms are not applicable to all devices.

1.5 V

Figure 2. Load Circuit and Voltage Waveforms