[sdiy] Best Op-Amps / oscillation

Ove Ridé nitro2k01 at gmail.com
Thu Nov 8 05:12:01 CET 2018


A TL07x or LM741, even one made today, has internal frequency compensation,
which will limit its bandwith to reduce the risk of oscillation. Assuming
the device is made to spec, it's part of the "contract" that a new part
will behave identically in this regard, despite being made with a newer
process. Of course, all bets are off if you're using a different opamp
that's not sold as a TL074.

On Wed, 7 Nov 2018, 20:43 cheater00 cheater00 <cheater00 at gmail.com wrote:

> Not even TL074 is a replacement for TL074 as the improved process and
> bandwidth today compared to the 1970s means if you replace a 1970s one with
> a modern one it will behave differently. My question is if someone's seen a
> modern op amp of the TL074 style oscillate where a 1970s version wouldn't?
> I think that's a good possibility but don't want to spread FUD.
>
> On Fri, 26 Oct 2018, 07:20 <rsdio at audiobanshee.com wrote:
>
>> Yeah, there are literally 10,000 choices when it comes to op-amps. There
>> are so many parameters.
>>
>> Sometimes, certain parameters make no difference at all in your circuit.
>> Other times, the parameters make a small difference, so you balance the
>> tradeoffs. Then, of course, certain circuits might demand the best possible
>> performance in one parameter or a few, so you have to balance cost versus
>> performance and tradeoffs with less important issues.
>>
>> Your best bet is to study what Jung and other have written so that you
>> understand which parameters matter in your case, and then use something
>> like Mouser’s parameter selection database to narrow in on a few choices
>> out of ten thousand.
>>
>> When you design, stick to common op-amp packages. When you build, be sure
>> to try out several options that have critical parameters in the range that
>> you need. Last time I ended up going through four op-amps before finding
>> one with low distortion and rail-to-rail performance (since I had USB 5 V
>> power as a limit).
>>
>> Brian
>>
>>
>> On Oct 25, 2018, at 9:11 PM, Tony K <weplar at gmail.com> wrote:
>> > Do yourself a favour and try to get your hands on Walter Jung's "IC
>> Op-Amp Cookbook" , any edition. It's the bible on op-amp design, selection,
>> advantages of each type etc.
>> >
>> > What are you trying to improve on? Noise, input bias? slew rate? Lo
>> noise.. That aforementioned book covers all these.
>> >
>> > On Oct 25, 2018, at 10:31 PM, Youssef Menebhi <
>> youssef.menebhi.79 at gmail.com> wrote:
>> >> I wanted to ask, generally, to the list - if there was a simple
>> >> replacement for the TL084/74 that would improve the overall "quality"
>> >> of the signal. I tend to use the TL084 by default, but have always
>> >> wondered if there would be some great improvement in using more
>> >> precisely-designed chips. Does anyone have any experiences with this?
>>
>>
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