TTL&CMOS families

Discussion in 'General Electronics Chat' started by alitex, Jul 22, 2007.

  1. alitex

    Thread Starter Active Member

    Mar 5, 2007
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    what the difference between TTL & CMOS IC'S ??
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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    There is no short answer to your question.

    Aside from the obvious difference of cmos (complimentary metal oxide semiconductor) versus ttl (transistor-transistor logic), the major difference is the difference in power consumption by the two logic families.

    Standard TTL will draw several milliamps of supply current while cmos draws several microamps. This hundred fold decrease in current consumption makes cmos very attractive from a designer's perspective since the power supply costs often account for a major percentage of the design cost.

    hgmjr
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    In addition to what hgmjr said, TTL requires a Vcc of +4.75 to +5.25 volts, where CMOS can operate over a relatively wide range of voltage.

    CMOS is generally much slower than TTL, but not much of a concern unless you're getting into the MHz range.

    CMOS is much more susceptible to damage by static discharge than TTL.

    TTL is ancient technology - it's been around 30+ years.

    CMOS is much newer, but is still pretty old technology.
     
  4. Distort10n

    Active Member

    Dec 25, 2006
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    What about LVTTL, huh huh huh? :p

    EDIT:

    NM...bad joke.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Bwahaha! :D

    Yeah, there's a slew of technologies out there now - it's nice to have choices. :) Didn't want to confuse the thread originator with more than what they were asking for.

    In 1980, I built some equipment using MECL IC's (Motorola ECL, Emitter Coupled Logic). The particular board was being clocked at 117 MHz, which was at the bleeding edge of the technology of the day. It doubled as a room heater. ;) I can't remember how much power it drew, but it was pretty significant.
     
  6. cumesoftware

    Senior Member

    Apr 27, 2007
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    Also, TTL and CMOS logic levels are different. See this page here:
    http://www.interfacebus.com/voltage_threshold.html

    Note that the "74HC/74HCT" family is CMOS as well, but the inputs and outputs ate TTL compatible, so the logoc levels will be the same as in the case of a TTL family (74, 74S, 74L, 74LS, 74F).
     
  7. alitex

    Thread Starter Active Member

    Mar 5, 2007
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    really i need all TTL and CMOS series and definition it
    thank u in advance
     
  8. techroomt

    Senior Member

    May 19, 2004
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    "i need all TTL and CMOS series and definition" , wow! all in all, good characterisics were given here - different voltage levels, power consumptions, speed, and logic (voltage) trigger levels. and, there are a few more. please realize there are many cmos and ttl families, and the differences between them are many. if you email me i will give you a list of the families to the best of my ability.
     
  9. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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  10. alitex

    Thread Starter Active Member

    Mar 5, 2007
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    this is my email
    vvalivv@hotmail.com
    thankx
     
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