[time-nuts] Subs for obsolete chips in pictic

Azelio Boriani azelio.boriani at screen.it
Mon Dec 12 03:57:37 EST 2011


The 74HC series can handle 6V levels too. The 74HCT series is a 5V logic
family.

On Sun, Dec 11, 2011 at 9:38 PM, Stanley <timenuts at n4iqt.com> wrote:

> The 74AC175 can not be subituted as the circuit needs the higher voltage
> output,  contact me off list  if you need a few parts, or use the surface
> mount PC board as these parts are still around. See options here :
> http://www.ko4bb.com/dokuwiki/**doku.php?id=precision_timing:**pictic<http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:pictic>
>
> Stanley
>
> ----- Original Message ----- From: "Azelio Boriani" <
> azelio.boriani at screen.it>
> To: "Discussion of precise time and frequency measurement" <
> time-nuts at febo.com>
> Sent: Sunday, December 11, 2011 2:15 PM
> Subject: Re: [time-nuts] Subs for obsolete chips in pictic
>
>
>  Better use 74HC or 74HCT parts, the 74F should be TTL FAST parts that
>> require high input current to be driven correctly.
>>
>> On Sun, Dec 11, 2011 at 9:04 PM, Chris Albertson
>> <albertson.chris at gmail.com>**wrote:
>>
>>  Looking at the picric II schematic.  Trying to decide on the bet
>>> substitute parts for some obsolete parts.
>>>
>>> It uses a few 74ACxxx locic family parts that are no longer made.   I
>>> think the "74H" or "74F" series should work  What do you think?  I may
>>> have to adapt an SMD part.     They have to work on 5V supply and the
>>> clock is 10MHz.   There is also a discontinued op amp but they are
>>> easy to sub.
>>>
>>> --
>>>
>>> Chris Albertson
>>> Redondo Beach, California
>>>
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>
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