+18v and -9v in a JRC4558? Is posible?

Started by Yoshi, March 25, 2022, 10:38:04 AM

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Yoshi

hello, I´ve a simple (and maybe dum) question

Can I supply, in a JRC4558 Op-Amp, with +18v in Pin 8 and -9v in pin 4? This to create a 36v op amp?

Thanks

vigilante397

You absolutely can, that's how Klon does it. You can still do a voltage divider on the 9V input for a +4.5V vref, which is brilliant as it's still right in the middle of +18V and -9V.
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Yoshi

Yeah!!!.... But what happen is I use +18v and -18v ... the vref needs to be +9v?

r080

In that case, your VRef is just "ground". If you are going there, you can search for circuits with bipolar supplies to give you ideas.
Rob

antonis

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

idy

It is only rated to +-15v. Magic smoke.

ElectricDruid

Quote from: idy on March 25, 2022, 02:14:18 PM
It is only rated to +-15v. Magic smoke.

Depends on the *exact* chip. There are some 4558's that are rated at +/-18V as the absolute max (which is equivalent to saying that +/-15V is the largest sensible supply voltage) and there are some that say +/-22V, which would make +/-18V possible.

You'd have to find a datasheet for the exact/particular version of the 4558 that you're using and make sure. Honestly though, I'm not sure I'd bother pushing it that close to the limits. What's wrong with a reliable +/-15V, which pretty much every op-amp in history was designed for?! And if +18V/-9V is the best way to get close to that, then perhaps that's the best way.

HTH



PRR

All those older chips are rated 36V, or +/-18V. They really prefer you use +/-15V which was once a real popular thing.

> +18v in Pin 8 and -9v in pin 4? This to create a 36v op amp?

Counting fingers and toes on me and the dog, that seems to be 27V, not 36V.
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antonis

Quote from: PRR on March 25, 2022, 11:14:16 PM
Counting fingers and toes on me and the dog, that seems to be 27V, not 36V.

I feel sorry for your amputee dog, Paul.. :icon_redface:

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

duck_arse

Quote from: antonis on March 26, 2022, 08:26:22 AM
Quote from: PRR on March 25, 2022, 11:14:16 PM
Counting fingers and toes on me and the dog, that seems to be 27V, not 36V.

I feel sorry for your amputee dog, Paul.. :icon_redface:

my dog has no nose.
You hold the small basket while I strain the gnat.

antonis

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..