An external timing capacitor may be connected between Cext and Rext/Cext (positive).
To use the internal timing resistor of 'LS422, connect Rint to VCC.
For improved pulse width accuracy and repeatability, connect an external resistor between Rext/Cext and VCC with Rint open-circuited.
To obtain variable pulse widths, connect an external variable resistance between Rint or Rext/Cext and VCC.
The 'LS422 and 'LS423 are identical to 'LS122 and 'LS123 except they cannot be triggered via clear.
These d-c triggered multivibrators 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 data). The 'LS422 contains an internal timing resistor that allows the circuits to be used with only an external capacitor, if so desired. Once triggered, the basic pulse width may be extended by retriggering the gated low-level-active (A) 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 transition rates as slow as 0.1 millivolt per nanosecond. The 'LS422 Rint 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 SN74LS423 are characterized for operation from 0°C to 70°C.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | Retriggerable Monostable Multivibrators datasheet | 01 Mar 1988 | |
| Application note | Designing With the SN74LVC1G123 Monostable Multivibrator (Rev. A) | PDF | HTML | 13 Mar 2020 | |
| Selection guide | Logic Guide (Rev. AB) | 12 Jun 2017 | ||
| Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 02 Dec 2015 | ||
| User guide | LOGIC Pocket Data Book (Rev. B) | 16 Jan 2007 | ||
| Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 08 Jul 2004 | ||
| Application note | TI IBIS File Creation, Validation, and Distribution Processes | 29 Aug 2002 | ||
| Application note | Designing With Logic (Rev. C) | 01 Jun 1997 | ||
| Application note | Designing with the SN54/74LS123 (Rev. A) | 01 Mar 1997 | ||
| Application note | Input and Output Characteristics of Digital Integrated Circuits | 01 Oct 1996 | ||
| Application note | Live Insertion | 01 Oct 1996 |
For additional terms or required resources, click any title below to view the detail page where available.
The 14-24-LOGIC-EVM evaluation module (EVM) is designed to support any logic device that is in a 14-pin to 24-pin D, DW, DB, NS, PW, DYY or DGV package,
| Package | Pins | Download |
|---|---|---|
| PDIP (N) | 16 | View options |
| SOIC (D) | 16 | View options |
| SOP (NS) | 16 | View options |
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