[time-nuts] Subs for obsolete chips in pictic

Stanley timenuts at n4iqt.com
Sun Dec 11 15:38:33 EST 2011


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

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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