SN74LV123A: SN74LV123AD monostable MV having Consistency issue in pulse with .

Jinith P

Part Number: SN74LV123A
Other Parts Discussed in Thread: SN74LVC1G123

We are using SN74LV123AD as monostable Multivibrator for generating 15 Second and 5 Second pulse.

While testing we are not getting consistent pulse output.

It varries from 15.8 Second to 13.5 Second in each Trigger.

We used Rext: 0.1% tolerance and Cext: 10% tolerance.

0 Jinith P over 1 year ago

Rext1=1.3M and Cext1= 10uF.

Rext2= 400K and Cext= 10uF.

0 Clemens Ladisch over 1 year ago

Guru 270760 points

What is the specified leakage current of your capacitor? If it is not much less than the current through Rext, it will affect the charging time.

If you want more accuracy, you have to use a clock derived from a crystal oscillator. Nowadays, you'd use a microcontroller.

0 Jinith P over 1 year ago in reply to Clemens Ladisch

Please suggest any Ti part which will provide precise re-triggerable pulse of 15 Second.

Please suggest any Ti replacement part for Analog Device iC 'LTC6993'

0 Clemens Ladisch over 1 year ago in reply to Jinith P

Guru 270760 points

The LTC6993 has an internal oscillator. There is no exact replacement from TI.

The SN74LVC1G123 has only one channel. But any RC-based timer requires a precise and low-leakage capacitor.

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