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I have a binary counter which is the following : https://www.onsemi.com/pdf/datasheet/mc14020b-d.pdf

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I want to reset this counter with a signal. I want this signal to be the narrower, ie the length of the pulse to be minimum. But I have to verify that the narrower signal is still took into account by the counter. I imagine that the the length of the pulse cannot be as small as I want. There is a mention about "Reset pulse width" into the datasheet but I do not know if it is that data that I have to consider and if there are other parameters to consider. I do not want to take any risks

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Here is a better binary counters : https://www.mouser.fr/datasheet/2/308/1/MC74HC4020A_D-2315492.pdf

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The reset pulse width is lower as the reset recovery time compared to the MC14020B but what is strange is that the maximum input rise time is very large ? What does "Maximum input Rise and Fall times" ? Does I have to consider that my pulse needs to be superior to the reset pulse width + the reset recovery time + the rise/fall time ?

Have a nice day :)

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  • \$\begingroup\$ Yes, that is the requirement you must meet. Note the huge discrepancy between minimum and typical values. \$\endgroup\$
    – Dave Tweed
    May 26, 2021 at 10:22
  • \$\begingroup\$ @DaveTweed I found a better binary counter but there is still an information that I do not get. Could you please help me ? See my edited post \$\endgroup\$
    – Jess
    May 26, 2021 at 14:35

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When speed matters, you won’t want to use 4xxx family high voltage logic and choose a family with a lower maximum Vdd.

The reasons for this is that newer, much smaller channels, have lower breakdown voltage, lower capacitance, lower RdsOn like 50 ohms for 74HCxx vs ~300 to 3k ohms for 4xxx family (18V to 3V) which on the CMOS drivers work fine but slower.

In your case you want to consider the largest pulse width, & recovery time and also derate for case temperatures above 25’C where they run slower due to higher RdsOn.

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  • \$\begingroup\$ Thank you for your answer. I found a better binary counter but there is still an information that I do not get. Could you please help me ? See my edited post \$\endgroup\$
    – Jess
    May 26, 2021 at 14:34
  • \$\begingroup\$ Huh? Max rise time means slow on input, not output. That’s irrelevant \$\endgroup\$ May 26, 2021 at 15:02
  • \$\begingroup\$ That's mean I must apply a signal faster than rise/fall time specified ? \$\endgroup\$
    – Jess
    May 26, 2021 at 15:08
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    \$\begingroup\$ Yes............. \$\endgroup\$ May 26, 2021 at 15:38
  • \$\begingroup\$ If you’re still concerned about speed , try the LV4060 which includes a clock rated for 100MHz @ 3V mouser.com/datasheet/2/916/74LV4060-1598056.pdf \$\endgroup\$ May 26, 2021 at 15:49

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