CMOS opamp 18V+, RR in and DIP-14?

LMC6484 with a 3V zener in the supply lead?

Cheers

Phil Hobbs

It's good that you're not picky, Joerg.

(And alas no, I haven't got a clue.)

The zener is unfortunately not possible because that would be a hack where the whole certification goes out the window. Only a part change can be justified at this point. The LMC6484 is abs maxed at 16V and we have a nominal 15V supply with the usual tolerances. That would be a white-knuckle ride. If it was abs max 18V it would be a perfect fit.

I thought about changing the supply voltage but that has a whole slew of ramifications.

I was recently looking at an announcement for an opamp that is specifically EMI hardened. But I can't remember where. Analog Devices, I think.

But DIP14? Try a museum maybe!

So tighten the PS tolerance, e.g. +15V, +0/-5%.

Cheers

Phil Hobbs

So tighten the PS tolerance, e.g. +15V, +0/-5%.

Cheers

Phil Hobbs

Jelly bean LMC660 would be easy to get but Vddmax is 16V. I found AD8548 cmos with 18V rating but only soic not Dip.

piglet

It's not that easy when there is an existing design and the regulator doesn't come in such tight tolerance. It is also an application where I'd like to have a little more margin to abs max than 6%.

The only items I am picky with are usually beer and food. No blue cheese in the food and also no cinammon or other weird stuff in my beer.

Yes, there are some. When I tried the bipolar ones were better than non-hardened but couldn't hold a candle to CMOS.

I know :-(

The LMC comes in DIP but only 16V max so we'd have to lower the supply rail for everything. It might boil down to either that or SOIC-DIP adapters.

Yup, that's why I posted here. Hoping I have overlooked a candidate or maybe one of the niche packagers makes a DIP or something semi-custom that we could piggyback onto.

Hi, Joerg:-

TI's TLC27M/L LinCMOS series might do. Abs max supply voltage is 18V. I've used them at +/-8V nominal in a production design. Old, stable design. I think ST makes a part that's similar, not sure if it's an exact second source.

Output swings from close to the neg rail to a couple volts below positive, inputs work to below the negative rail.

--Spehro Pefhany

Best regards, Spehro Pefhany

If you build an adapter, you could add EMI filtering to a standard opamp. Fab a couple thousand of them.

We had to do this when Maxim, well, Maxim'ed us.

(about 3000 times)

Yeah, if push comes to shove we'll have to do that. CMOS amps would not really need much in terms of EMI filtering as they do not have parasitic rectifier paths.

St Micro has a cmos opamp with the RR input & output. That, or possibly the ti near equivilent, are available in dip packages. If you haven't checked these yet, take a look.

Hul

Joerg wrote:

Thanks! That looks like a perfect fit, even comes in different offset and bandwidth flavors. Most of all the DIP part is stocked.

Yes, thanks, Spehro just recommended the TLC27 which appears to fit nicely. He mentioned ST as well but ST's web site is quite messy and I haven't found anything on that so far. But the TI part works.

Well, nearly. The 'abs max' isn't the 'recommended max'' supply voltage ( 16V ).

Ok in our case. The supply voltage is 15V so within the recommended range of 4-16V and it is well below abs max.