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yet another op-amp question... — Parallax Forums

yet another op-amp question...

ArchiverArchiver Posts: 46,084
edited 2003-08-29 19:16 in General Discussion
I'm looking for a filter for a high noise application and was sent a
simple introduction to filters.

The text describes the use commutating auto-zero (CAZ) op-amp, like
the MAX420CPA.

these puppies are expensive. almost $9.00 each, plus shipping. I
know Maxim has a great samples offer but I hate to rely on sample
lead times, it's been almost 3 months since I requested a MOSFET
driver chip...


Is there a less expensive alternative ?

Dave

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-08-29 17:54
    filters must be selected for specific applications to be effective. Check
    out Murata-Erie for filters and filter information if you want to purchase
    ready made ones. If you want to roll your own, the Amateur Radio Handbook
    from the ARRL (arrl.com) has lots of info.

    jim
    http://www.geocities.com/jimforkin2003/


    Original Message
    From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=g-i043uDcvhAZNevKMoeradnrKF2Ly4PzsA0u7qeTkVmfjhbOMkdMLTMRvP9Dl9BDGjis55V4HA]davemucha@j...[/url
    Sent: Friday, August 29, 2003 11:37 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] yet another op-amp question...


    I'm looking for a filter for a high noise application and was sent a
    simple introduction to filters.

    The text describes the use commutating auto-zero (CAZ) op-amp, like
    the MAX420CPA.

    these puppies are expensive. almost $9.00 each, plus shipping. I
    know Maxim has a great samples offer but I hate to rely on sample
    lead times, it's been almost 3 months since I requested a MOSFET
    driver chip...


    Is there a less expensive alternative ?

    Dave




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  • ArchiverArchiver Posts: 46,084
    edited 2003-08-29 19:16
    >I'm looking for a filter for a high noise application and was sent a
    >simple introduction to filters.
    >The text describes the use commutating auto-zero (CAZ) op-amp, like
    >the MAX420CPA.
    >these puppies are expensive. almost $9.00 each, plus shipping. I
    >know Maxim has a great samples offer but I hate to rely on sample
    >lead times, it's been almost 3 months since I requested a MOSFET
    >driver chip...
    >Is there a less expensive alternative ?
    >Dave

    CAZ op-amps main claim to fame is low low DC offset. Does your
    frequency band of interest go down to DC? If not, there are a lot of
    non-CAZ op-amps that would be a lot cheaper. What is the bandwidth,
    low and high frequency limits of your signal? What about the
    extraneous noise source?

    I often use the Linear Tech LT1051 ($5 each CAZ), and they are well
    worth the price when DC accuracy is important.

    -- Tracy
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