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2

Operating Rules

1.

vary from 0 to any necessary value. For small time con-

stants high-grade mica, glass, polypropylene, polycar-

bonate, or polystyrene material capacitors may be

used. For large time constants use tantalum or special

aluminum capacitors. If the timing capacitors have

leakages approaching 100 nA or if stray capacitance

from either terminal to ground is greater than 50 pF the

timing equations may not represent the pulse width the

device generates.

2.

ing diode is often required for standard TTL one-shots

to prevent high inverse leakage current (Figure 1).

However, its use in general is not recommended with

retriggerable operation.

3.

defined as follows:

[K

≈ 0.28]

FIGURE 1.

4.

FIGURE 2.

5.

To obtain variable pulse width by remote trim-

ming, the following circuit is recommended:

FIGURE 3.

6.

The retriggerable pulse width is calculated as

shown below:

T

= T

The retriggered pulse width is equal to the

pulse width plus a delay time period (Figure

4).

FIGURE 4.

7.

must be kept as close to the one-shot device

pins as possible to minimize stray capaci-

tance, to reduce noise pick-up, and to reduce

I

× R and Ldi/dt voltage developed along their

pins (6) and (7) or pins (14) and (15) is greater

than 3 cm, for example, the output pulse width

might be quite different from values predicted

from the appropriate equations. A non-induc-

tive and low capacitive path is necessary to

cycle of its operation so that the output pulse

width will be accurate.

8.

good high-frequency standards and practices

ground return leads do not cause interaction

between one-shots. A 0.01

µF to 0.10 µF

bypass capacitor (disk ceramic or monolithic

each device. Furthermore, the bypass capaci-

as space permits.

Note: For further detailed device characteristics and output performance

please refer to the One-Shot Application Note, AN-366.