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Functional Description

The DM96LS02 dual retriggerable resettable monostable

multivibrator has two DC coupled trigger inputs per func-

tion, one active LOW (I0) and one active HIGH (I1). The I1

input and I0 input of the DM96LS02 utilize an internal

Schmitt trigger with hysteresis of 0.3V to provide increased

noise immunity. The use of active HIGH and LOW inputs

allows either rising or falling edge triggering and optional

non-retriggerable operation. The inputs are DC coupled

making triggering independent of input transition times.

When input conditions for triggering are met, the Q output

goes HIGH and the external capacitor is rapidly discharged

and then allowed to recharge. An input trigger which occurs

during the timing cycle will retrigger the circuit and result in

Q remaining HIGH. The output pulse may be terminated (Q

to the LOW state) at any time by setting the Direct Clear

input LOW. Retriggering may be inhibited by tying the Q

output to I0 or the Q output to I1. Differential sensing tech-

niques are used to obtain excellent stability over tempera-

ture

and

power

supply

variations

and

a

feedback

Darlington capacitor discharge circuit minimizes pulse

width variation from unit to unit. Schottky TTL output stages

provide high switching speeds and output compatibility with

all TTL logic families.

Logic Diagram

Operation Notes

TIMING

are required as shown in the Logic Diagram. The value of

available. If, however, the capacitor has significant leakage

the pulse width obtained.

1000 pF is determined as follows:

is in

µF, t is in ms.

graphs.

5. To obtain variable pulse width by remote trimming, the

following circuit is recommended:

kept as close to the circuit as possible to minimize stray

capacitance and reduce noise pickup.

ground leads do not cause interaction between one shots.

Use of a 0.01

µF to 0.1 µF bypass capacitor between V

CC

and ground located near the circuit is recommended.

TRIGGERING

1. The minimum negative pulse width into I0 is 8.0 ns; the

minimum positive pulse width into I1 is 12 ns.

2. Input signals to the DM96LS02 exhibiting slow or noisy

transitions can use either trigger as both are Schmitt trig-

gers.

3. When non-retriggerable operation is required, i.e., when

input triggers are to be ignored during quasi-stable state,

input latching is used to inhibit retriggering.

4. An overriding active LOW level direct clear is provided

on each multivibrator. By applying a LOW to the clear, any

timing cycle can be terminated or any new cycle inhibited

until the LOW reset input is removed. Trigger inputs will not

produce spikes in the output when the reset is held LOW. A

trigger transition, the circuit will respond to the trigger.