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A quicker LM393 ?

Discussion in 'Electronic Components' started by Eeyore, Nov 17, 2007.

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  1. Eeyore

    Eeyore Guest

    Looking for an inexpensive commodity dual comparator that's a little quicker
    than the ubiquitous LM393.

    Suggestions ?

    Graham
     
  2. I always have problems when I build a LM393 on strip board prototypes
    with MHz oscs on the transistions. I've tried the usual positive
    feedback tricks, etc

    Is it just me?


    Martin
     
  3. It might be. ;-)

    I generally have very good luck with plugboard prototypes
    using the LM393.

    John Popelish
     
  4. The LM319 dual is not a drop in replacement, nor a similar
    design with just higher speed. but it is faster.

    http://cache.national.com/ds/LM/LM119.pdf

    Though there are lots of variations on the 393, made by
    various companies, like Linear Technology, many are slower,
    with lower power consumption and work at lower voltage.
    There may be something out there, faster but otherwise
    similar, but it will be no where as commonly available or
    cheap as the 393.

    If something with different internal design might work, what
    are your requirements?
     
  5. <sigh>
    I had better get a lower bandwidth scope then




    Martin
     
  6. The LMV393 may be slightly faster. I like TI's
    cmos TLC3702 version, with active-pullup outputs.
    Although it's officially slower than the LM393,
    in some circuits with high-value pullup resistors
    it might be faster. The TLV3702 is an attractive
    nanopower version that's quite slow. Yawn...
     
  7. Tim Williams

    Tim Williams Guest

    LM360 is blinding fast TTL. Single per package and gobs of current, so not
    exactly just "a little" quicker.

    LM319 as mentioned is about inbetween the 393 and 360. IIRC, the 319 comes
    in single units as well.

    Tim
     
  8. Ah, I forgot about the max907, same pinout, but very
    fast, almost 100x faster than the lm393. Sadly Maxim
    has discontinued it: "This product was manufactured
    for Maxim by an outside wafer foundry using a process
    that is no longer available." But if you want to give
    Maxim another chance, their max942 is about 5x faster
    than the lm393 The max942 has an active pullup. The
    miniDIP is $3.62 at Newark. Free samples from Maxim.

    Or you might try TI's tlc372 and tlv2352 parts, they
    are cheap and may be a bit faster than the lm393.
     
  9. Oh, one thing, most of these are low-voltage parts,
    best used at 0/+5V, etc.; no +/-15V for these guys!
     
  10. John Larkin

    John Larkin Guest

    LVDS receivers are ns-speed comparators for around 50 cents. They do
    tend to have built-in DC offsets.

    John
     
  11. Eeyore

    Eeyore Guest

    Hard for me to say. The last time I used stripboard was 1990.

    Graham
     
  12. Eeyore

    Eeyore Guest

    A couple of hours after I posted this I remembered the 319. I had thought it was
    of the same performance as the 393/339 but purely a single.

    In fact it looks like it may be just the ticket.

    It's for use in a switching PSU. It looks like 'rolling my own' is the best bet
    for my simple low drop-out buck regulator.

    Graham
     
  13. Just about to wire up a bit of stripboard that I managed to find, with
    a 74HC221, a 74hc86 , lm393 and an AT89s4051 so that I can decode
    smpte timecode played from a laptop. It's not worth waiting for a pcb
    from Olimex


    Martin
     
  14. Which LVDS parts do you use?

    Thanks


    Martin
     
  15. Eeyore

    Eeyore Guest

    Have you looked at pcb express ?

    Graham
     
  16. Not recently, but Olimex is generally fine for me, this will be up
    and programmed by tea time today, I only decided I needed it yesterday
    afternoon, after a couple of mugs of rioja


    Martin
     
  17. Eeyore

    Eeyore Guest

    Do you find Olimex a good prototype/small quantity production supplier ? What are their
    turnaround times like ? Any info gladly received ! I'm looking for a decent supplier
    right now. What CAD file formats do they support too ?

    Graham
     
  18. check your email


    Martin
     
  19. Eeyore

    Eeyore Guest

    Thanks.

    Graham
     
  20. Eeyore

    Eeyore Guest

    Oh crikey, just remembered ! A quasi-random unconnected thought. Ages back you
    mentioned an outfit that had a compiler for the former 'Alesis' DSP chips.

    I thought I'd bookmarked it but can't find it. Can you refresh my memory ?

    Graham
     
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