[sdiy] Unused opamps in multi-opamp ic / Re: triangle core VCO comparators

[rsdio at audiobanshee.com]

What I find interesting is that Figure 4 is actually an Open Collector NOR Gate, not NAND. I suppose that anyone can make a mistake, but in a document that's supposed to be teaching the right way to do things, it's almost hilarious that there is a mistake so obvious.

I went searching for SLOA067 on Texas Instruments' web site, and it's no longer there. SBOA092A, Handbook of Operational Amplifiers, mentions it as the first reference, but clicking on the link ends up at a dead end.

It's a good thing that other web sites keep this stuff around.

Brian


On Feb 25, 2016, at 12:27 PM, Rick Jansen <rick.jansen at xs4all.nl> wrote:
> 4.2.1 in that article has an interesting section on what to do with unused opamps in a multi-opamp ic...  Comments? (Apparently I did it wrong, a few times..)
> 
>> On 25 Feb 2016, at 21:15, Rick Jansen <rick.jansen at xs4all.nl> wrote:
>> 
>> This month's (March/April) NL Elektor has an article on the difference between actual comparators and opamps. True comparators are (much) faster, and can reach rail voltages, and so not rely on the amplification factor of the opamp. Also, the output stage of many opamps is not suited for comparator functions, and can even damage them.
>> 
>> The end of the article refers this document: http://encon.fke.utm.my/nikd/latest/sloa067.pdf
>> 
>> Bruce Carter : opamps and comparators , don't confuse them.
>> 
>>> On 18 Feb 2016, at 01:48, Chris McDowell <declareupdate at gmail.com> wrote:
>>> I'm wondering about the choice of comparator for triangle core VCOs. I've seen it done a few ways, like Thomas Henry's discrete comparator, or the LM311 in J3RK's (STROH Modular) VCOs on Muffs, and my own builds just use TL07x and work -pretty much- great. But I'm wondering what the experiences and preferences are of you here on the list. Fast op amp? Real comparator? Doesn't matter? I'm aware that it only matters as much as HF-Tracking matters, but I'm interested in opinions anyway.