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Retriggering Data

t

MIR

t

RT

t

PLH

t

w

Input

Output

t

=t +t

=(K

R

RT

w

PLH

T

T

PLH

´

´ C ) + t

Where:

t

=MinimumInputRetriggering Time

MIR

t

=PropagationDelay

PLH

t

=Retrigger Time

RT

t

=OutputPulseDurationBeforeRetriggering

w

Input

Output

t

=Minimum TimeBetweentheEndoftheSecondInputPulseandtheBeginningoftheRetriggeredOutput

MRT

t

=15ns

MRT

t

MRT

SN74AHC123A-EP

DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATOR

SCLS703A – JULY 2006 – REVISED MARCH 2007

APPLICATION INFORMATION (continued)

NOTE: Operation of the device at these or any other conditions beyond those indicated under "recommended operating

conditions" is not implied.

The minimum input retriggering time (tMIR) is the minimum time required after the initial signal before retriggering

the input. After tMIR, the device retriggers the output. Experimentally, it also can be shown that to retrigger the

output pulse, the two adjacent input signals should be tMIR apart, where tMIR = 0.3 × tw. The retrigger pulse

duration is calculated as shown in Figure 3.

Figure 3. Retrigger Pulse Duration

The minimum value from the end of the input pulse to the beginning of the retriggered output should be

approximately 15 ns to ensure a retriggered output (see Figure 4).

Figure 4. Input/Output Requirements

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