please dont rip this site

Logic Familys

Also:

[begin-quote]

Logic Family Choices

With about 20 logic families now extant, some comments are in order about which to use for teaching lab excercises and projects. You are aware, I sincerely hope, that Morse Teaching Center policy is to simplify ordering and to lessen confusion among TAs and students by insisting on close adherence to a set of Recommended Parts. To be sure, such a list will never be complete, so we are willing to expand it as your needs evolve, but the process should be governed by informed choice. We don't want our lab activities to become historic restoration projects.

This first figure comes from a Texas Instruments promotional brochure but is a convenient way of showing most (not all) logic families and where they fit generationally. The original TTL family (e.g. 7400, 7493) had its heyday 20 years ago and is thoroughly obsolete. One of its prominent successors, the 74ALSxxx family, is still quite current and readily available.

But with CMOS becoming the hugely dominant force in logic integration, this is what we should expose students to. The best choice for general logic experiments and design is the 74HCxxx family. So the modern 74HC76 will be a supply-voltage (+5V) and pin-compatible dual flip-flop like the old 7476. For those interested in more details, the electrical characteristics of the major families are in Table 9.1 (pictured below) from Horowitz & Hill "The Art of Electronics," with much additional information in the rest of chapt. 9

Not all logic functions you might will be available in the modern HC and HCT families, especially when it comes to specialized interface functions like display drivers. In those cases we need to resort to ALS or even LS. But always please consider if redesign can bring your logic needs into the HC family. When a design has to mix logic families, some care may be indicated as per the interconnection guidelines in Horowitz & Hill Table 9.2. (pictured below)

Lou Berman and I are ready to work with you on clarifying any particulars of logic IC (and other component) choices, to bring them into harmony with, and constructively evolve, our " Recommended Parts" library.


TABLE 9.1. -- LOGIC FAMILIES
  tpd(’00)
(CL=50pF)
  Pdiss   Vsupply  
 
fclk(’74) (CL=0) IOL IIL Vth
Date
Family typ
(ns)
max
(ns)
max
(MHz)
@1MHz
(mW/gate)
@0.5V max
(mA)
max
(mA)
typ
(V)
min
(V)
nom
(V)
max
(V)
of intro

CMOS
   AC
   ACT
3 5.1 125 0.5 24 0 V+/2
1.4
2
4.5
5 or 3.3
5
6
5.5
1985
   HC
   HCT
9 18 30 0.5 8 0 V+/2
1.4
2
4.5
5
5
6
5.5
1982
4000B/74C @10V
@5V
30
50
60
90
5
2
1.2
0.3
1.3
0.5
0
0
V+/2 3 5-15 18 1970

TTL
   AS 2 4.5 105 8 20 0.5 1.5 4.5 5 5.5 1980
   F 3.5 5 100 5.4 20 0.6 1.6 4.75 5 5.25 1979
   ALS 4 11 34 1.3 8 0.1 1.4 4.5 5 5.5 1980
   LS 10 15 25 2 8 0.4 1.1 4.75 5 5.25 1976

TABLE 9.2. -- LOGIC FAMILIES CONNECTIONS
TO
FROM
TTL HCT
ACT
HC
AC
HC, AC
@3.3V
NMOS
LSI
4000B,
74C
@5V
4000B,
74C
@10V
TTL OK OK A OK OK A B
HCT
ACT
OK OK OK NO OK OK B
HC
AC
OK OK OK NO OK OK B
HC, AC
@3.3V
OK OK NO OK OK B B
NMOS
LSI
OK OK A OK OK A B
4000B,
74C
@5V
OKa OK OK NO OK OK B
4000B,
74C
@10V
C C C C C C OK
(a) with limited fanout.
A - pullup to +5V, or use HCT as interface.
B - use i)OC pullup to +10V, or ii)40109, 14504, or LTC1045 level translator.
C - use 74C901/2, 4049/50, 14504, or LTC1045 level translator.

[end-quote -- from http://www.eng.yale.edu/ee-labs/morse/main.htm ]


Questions:


[begin-move]

Logic Familys

Logic Familys

A - Advanced

L - Low

S - Schottky

C - CMOS interface (not necessarily CMOS components but designed for connection to other CMOS devices)

T - TTL interface (not necessarily TTL components but designed for connection to other TTL devices) Devices are assumed to be TTL unless otherwise specified.

F - Fast TTL.

See also:

Questions:

[end-move]

Comments:


file: /Techref/logic/family.htm, 27KB, , updated: 2013/7/22 17:46, local time: 2024/10/14 11:32, owner: DAV-MP-E62a,
TOP NEW HELP FIND: 
98.80.143.34:LOG IN
©2024 PLEASE DON'T RIP! THIS SITE CLOSES OCT 28, 2024 SO LONG AND THANKS FOR ALL THE FISH!

 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF="http://techref.massmind.org/techref/logic/family.htm"> Logic Family</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

 

Welcome to massmind.org!

 

Welcome to techref.massmind.org!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .