Parameter Measurement Information

Unless otherwise noted, all input pulses are supplied by generators having the following characteristics:

• PRR ≤ 1 MHz

• ZO = 50 Ω

• tr ≤ 3 ns

• tf ≤ 3 ns

Note

All parameters and waveforms are not applicable to all devices.

CL

(1)

From Output

Under Test

Test

Point

A.

CL includes probe and jig capacitance.

B.

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

Figure 6-1. Load Circuit For Totem-Pole Outputs

From Output

Under Test

CL

(1)

RL = 1 kŸ

S1

Open

VCC

GND

A.

CL includes probe and jig capacitance.

B.

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

Figure 6-2. Load Circuit For Tri-State And Open-Drain Outputs

Table 6-1. Loading Conditions For Parameter

TEST

S1

tPLH (1), tPHL (1)

Open

tPLZ (3), tPZL (2)

VCC

tPHZ (3), tPZH (2)

GND

Open drain

VCC

(1)

tPLH and tPHL are the same as tpd.

(2)

tPZL and tPZH are the same as ten.

(3)

tPLZ and tPHZ are the same as tdis.

1.5 V

3 V

0 V

Input

tw

1.5 V

Figure 6-3. Voltage Waveforms Pulse Durations

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SN54AHCT240, SN74AHCT240

SCLS252P – OCTOBER 1995 – REVISED JANUARY 2025

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