polymer alum cap leakage

They seem to have a strong positive TC of leakage current. A little heat gunning gets them up to 60 uA, and they settle back near 2 when they cool off.

Haven't tried that. I'll let them soak a few days at reverse bias and then see.

I have a wonderful circuit that needs these to be bipolar, to maybe

-5. The alternate isn't as elegant.

Am 25.10.2016 um 02:41 schrieb John Larkin:

I have finally used these:

after checking a lot of other ones, without evidence of short-term failure. No nasty surprises after a year. Funny enough, the 5% were cheaper than 20% at Mouser.

regards, Gerhard

Nice, but expensive.

Luxury! You can buy 1000 LM358 for the equivalant of US $8.57 including domestic (China) shipping. 0.86 cents each.

--sp

Yes, it is an LM358. Not a great opamp by modern standards, but pretty good in absolute terms.

I don't understand why anyone would sell transistors or LEDs or opamps for a penny each.

My inventory shows several opamps around $8, and one for $13.

Your understanding is not required to take advantage of the price.

Then you should use them since you have already paid for them.

I understand enough to not buy no-name Chinese opamps.

Yup, that's what stock is for.

We have 106 different opamps in stock, and I think I'll add one more, OPA197.

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Oh I just started using the opa192 (opa2912) A FET with ~10 uV VOS.

George H.

Nice part. Under a buck in duals, even better. The specs remind me of the OPA140, which I'm quite fond of, but RRIO and much cheaper. Have to try it out.

Cheers

Phil Hobbs

After 5 days at -10 volts, all six caps in parallel are leaking 1.3 uA total. That's down 100:1 in 5 days, and still declining. You'd think that if there were some nasty electrochemical failure in the works, the current would be going up.

I had to switch to my big benchtop Fluke to resolve the drop across the 1K current shunt.

It's a gumdrop, but fairly fast, rrio, cheap, and works up to 32 volts. We generally prefer single SOT23s so we don't have to agonize over what to do with the other section.

It's c-load stable with a big ceramic cap, 10 uF or so, or a tantalum.

Do you know about the TCA0372? Dual 1 amp for 45 cents. C-load stable with the right cap.

Yup, I usually use them for making floating grounds and stuff--sometimes people want to use TIAs like souce-measure units (SMUs), and the simplest way to do that is to just move the common voltage around and fix it afterwards with a good diff amp.

I'd like it a lot better if it came in a powerpad package--it runs noticeably warm just from its quiescent current.

Cheers

Phil Hobbs

It does bring out the substrate on eight pins, which slurps a bunch of heat out.

Hey, it's 45 cents!

I'm quite aware of its appeal--it's the hangover I'm leery of. ;)

How much power are you dumping into that pour?

Cheers

Phil Hobbs

Worst case, a bit under two watts. That should be fine.