More VSS

[Mike Dillon]

Hi Bruce,

I don't have any referances here but this is in general what you are 
looking at.

SN74LS74AN

SN -> Who manufatured the device Signetics ?? MC is maybe Motorolla ?? 
74 -> "7400" series logig family 
LS -> low power shottky (sp) (Other common letters in this position are:
          F -> fast logic, HC -> high speed cmos, S -> Shottky, no letter original 7400 TTL series type.
           To some degree they will plug and play together but you have to watch their specs
            as mixing cross familys may reduce noise margins. the rat shack should have 
            a basic logic book that specs input-output specs for the different 
            familys.
74 -> D Flip flop (?? I don't have a TTL data book handy)
      This number goes between 00 (Inverter ??) up to 3XX or may be 4XX
      and all(most all) the 7400 sries parts with a common number in this 
      field do the same function ie. inverter, and or ...
AN    Usually a package code for what type of package it is in DIP, SIP, PLCC .....

So your other chip is a High speed CMOS something, I don't know off the top 
of my head what function a 86 is in the 7400 series.


Good luck Mike D.

      
> From diy_efi-owner at esl.eng.ohio-state.edu Wed Sep 30 15:17 CDT 1998
> Return-Path: <diy_efi-owner at esl.eng.ohio-state.edu>
> From: "Bruce Plecan" <nacelp at bright.net>
> To: <diy_efi at efi332.eng.ohio-state.edu>
> Status: RO
> 
> 
> -----Original Message-----
> From: jdzura at csc.com <jdzura at csc.com>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> Date: Wednesday, September 30, 1998 2:01 PM
> Subject: Re: More VSS
> 
> 
> >The DS-C304 is a ttl output Crystal oscillator. Nearly any frequency will
> do, but the slower the better. The frequency of the oscillator defines the
> width of the pulse coming out of the Xor gate. At 100 MPH, the VSS freq
> should be 2*100*2000, or 400KHz  right?  As long as the oscillator is 500
> KHz or above you should be OK.
> >I'm pretty sure Digikey has 1 MHz XO43 Style oscillators.
> 
> OK, I been thru the Newark, and Digi-key cats, and the 7474 are
> SN74LS74AN, is that the same part?.
> I can't find a DS-C304A anywhere...
> Is a MC74HC86N the right thing?.
> Bruce
> >
> >Let me know if you have any problems / questions.
> >
> >Joe D
> >
> >
> >
> >
> 
>