Will Not Trigger from Clear

D.C Triggered from Actve-High or Active-
Low Gated Logic Inputs

Retriggerable for Very Long Output Pulses,
Up to 100% Duty Cycle

Overriding Clear Teminates Output Pulse
‘L§422 Has Internal Timing Resistor

description
The 'LS422 and ‘S423 are identical to ‘LS122 and
'LS123 except they cannot be triggered via clear.
These d-c triggered mulrivibrators feature output-pulse-
width control by three methods. The basic pulse time is
programmed by selection of external resistance and
capacitance values (see typical application datal. The
‘LS422 contains an internal timing resistor that allows
the circuits to be used with only an external capacitor, if
so desired. Once triggerad, the basic pulse width may be
extended by retriggering the gated low-level-active (Al
or high-level-active (B) inputs, or be reduced by use of
the overriding clear. Figure 1 illustrates pulse control by
retriggering and early clear.
The 'LS422 and "LS423 have enough Schmitt hysteresis
to ensure jitter-free triggering from the B input with tran-
sition rates as slow as 0.1 millivolt per nanosecond. The
"LS422 Ripe is nominally 10 k ohms.
The SN54LS422 and SN54LS423 are characterized for
operation over the full military temperature range of
—55°C to 125°C. The SN74LS422 and SN74L5423
are characterized for operation from 0°C to 70°C.