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Re: Diff amps spec at 500ohms plus, why?

From	Joerg <news@analogconsultants.com>
Newsgroups	sci.electronics.design
Subject	Re: Diff amps spec at 500ohms plus, why?
Date	2017-12-23 11:42 -0800
Message-ID	<fa7pruFctqcU1@mid.individual.net> (permalink)
References	(6 earlier) <922r3d1ofvnjsvdo1fb613f0irc1l294n8@4ax.com> <fa5i1kFrsjlU1@mid.individual.net> <iNqdnQvLtPB-O6PHnZ2dnUU7-LHNnZ2d@supernews.com> <e9at3dlr7g3t4308rv5qbns07aufhsfi20@4ax.com> <K56dnV6IuajwN6PHnZ2dnUU7-RGdnZ2d@supernews.com>

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On 2017-12-23 11:11, Phil Hobbs wrote:
> On 12/23/2017 02:08 PM, John Larkin wrote:
>> On Sat, 23 Dec 2017 13:56:35 -0500, Phil Hobbs
>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>>> On 12/22/2017 06:16 PM, Joerg wrote:
>>>> On 2017-12-22 14:40, John Larkin wrote:

[...]

>>>>> But it's impressive how often nobody has the answer. A recent question
>>>>> invoked the response "That's an old Burr-Brown part. Nobody knows
>>>>> anything about it." (dual 14-bit TXDAC.)
>>>>>
>>>>
>>>> Or they might say "You have to go to Golden Sunset Senior Center and
>>>> ask
>>>> for resident Joe Smith".
>>>>
>>>> Just came across the THS6214 which looks more capabable than the others
>>>> but +/-5V would be at the very bottom supply range for this chip:
>>>>
>>>> http://www.ti.com/lit/ds/symlink/ths6214.pdf
>>>>
>>>> It's also long in the tooth. 2009 is almost ancient for telco chips.
>>>>
>>>
>>> A 100 MHz, 3600 V/us CFB _QUAD_ for two and a half bucks?  Where has
>>> this chip been all my life?

That one is old. Sometimes it is good to look at specialty markets since 
those chips are often not advertized in the regular analog marketplace. 
In the 80's we had similar problems where the only really fast opamps 
were from Harris but only came in the super-pricey mil-spec ceramic 
package, you had to call the utility before turning it one and they 
almost got hot enough to result in a blister after touching. Then I 
discovered the unsung heroes which were only marketed to engineers 
designing video recorders and hard drives. uA733 and such, those were a 
real bargain in all domains. Then some Japanese ICs that even our 
distributors didn't know about.

Same with discretes where PIN diodes were almost mil-pricing. Once I had 
to bypass our purchasing department because they wouldn't bypass "their" 
distributors which couldn't get that stuff. I ordered the diodes myself, 
in Malaysia, and that resulted in a VP office discussion where it got loud.

>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>
>> Four times as much heat to get rid of.
>
> Yeah, but the rather nice 200-MHz THS3091 that I've been using costs
> five bucks in reels and ten bucks in onesies.
>

And sometimes you just need this much muscle. Just like a 2-liter engine 
is more efficient but can't tow the 5-ton trailer.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Thread

Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-21 15:48 -0800
  Re: Diff amps spec at 500ohms plus, why? George Herold <gherold@teachspin.com> - 2017-12-21 18:53 -0800
    Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 09:31 -0800
  Re: Diff amps spec at 500ohms plus, why? Winfield Hill <hill@rowland.harvard.edu> - 2017-12-21 19:48 -0800
    Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 09:34 -0800
    Re: Diff amps spec at 500ohms plus, why? bloggs.fredbloggs.fred@gmail.com - 2017-12-24 09:37 -0800
  Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-21 19:55 -0800
  Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-21 19:59 -0800
    Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 09:39 -0800
  Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 12:07 -0800
    Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highland_snip_technology.com> - 2017-12-22 12:54 -0800
      Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 13:29 -0800
        Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highland_snip_technology.com> - 2017-12-22 14:06 -0800
          Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 14:19 -0800
            Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highland_snip_technology.com> - 2017-12-22 14:40 -0800
              Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 15:16 -0800
                Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-22 16:30 -0800
                Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-22 16:57 -0800
                Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-22 20:33 -0800
                Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-23 08:21 -0800
                Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-23 10:20 -0800
                Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-23 11:33 -0800
                Re: Diff amps spec at 500ohms plus, why? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-12-23 13:56 -0500
                Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-23 11:08 -0800
                Re: Diff amps spec at 500ohms plus, why? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-12-23 14:11 -0500
                Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-23 11:42 -0800
  Re: Diff amps spec at 500ohms plus, why? LM <sala.nimi@mail.com> - 2017-12-23 21:36 +0200
    Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-23 12:18 -0800
  Diff amps spec at 500ohms plus, why? Klaus Kragelund <klauskvik@hotmail.com> - 2017-12-25 00:56 -0800
    Re: Diff amps spec at 500ohms plus, why? krw@notreal.com - 2017-12-25 08:51 -0500
      Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-25 07:26 -0800
        Re: Diff amps spec at 500ohms plus, why? krw@notreal.com - 2017-12-25 10:46 -0500
          Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-25 07:51 -0800
            Re: Diff amps spec at 500ohms plus, why? krw@notreal.com - 2017-12-25 12:53 -0500
              Re: Diff amps spec at 500ohms plus, why? John Larkin <jjlarkin@highlandtechnology.com> - 2017-12-25 09:58 -0800
              Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-25 11:39 -0800
                Re: Diff amps spec at 500ohms plus, why? whit3rd <whit3rd@gmail.com> - 2017-12-25 17:16 -0800
                Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-27 16:17 -0800
                Re: Diff amps spec at 500ohms plus, why? Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-12-27 19:06 -0800
                Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-28 00:47 -0800
                Re: Diff amps spec at 500ohms plus, why? Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-12-27 16:38 -0800
        Re: Diff amps spec at 500ohms plus, why? George Herold <gherold@teachspin.com> - 2017-12-27 18:03 -0800
          Re: Diff amps spec at 500ohms plus, why? Joerg <news@analogconsultants.com> - 2017-12-28 00:50 -0800

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