please suggest me on opamp..

[rao]

Hi

I want to buy integrated circuit between 36 and 44V for my project. please suggest me basic operational amplifier, voltage regulators in this range and affordable. Thank you all. Have a happening Sunday.

[Dabbot]

What does your project do?

[rao]

want to construct regulated power supply which should supply 40V with OPAMP and NOT VOLTAGE REG .so i need some general purpose opamp (DIP, T0 package,etc) which could be used for through hole technology.

[schmitt trigger]

LM741A

[rao]

sir,

LM 741A is safer up to 36V.But my application will have maximum of 40V. Suggest me Some other opAMP where it has greater voltage than LM741..

[Dabbot]

Some variants of the 741 will allow an absolute maximum of 44V:
UA741I - https://www.st.com/content/ccc/resource/technical/document/datasheet/group1/d6/9e/4e/8a/fa/65/4c/d0/CD00001252/files/CD00001252.pdf/jcr:content/translations/en.CD00001252.pdf

[BravoV]

You are in India, are you willing to import say like Digikey and alike ?

Will you pay about US$50  for just one op-amp ? As India has crazy import tax regime, incl. the international shipping charge.

Bottom line is, what is the budget ? Other wise, what ever people suggest here will be useless.

[rao]

Sir,

   I could be able to spend 30 Indian rupees for an OPAMP( less than half a dollar) .

[BravoV]

Then just live with what ever available in your place, as you do NOT have the luxury of choosing the right op-amp as you want.

I doubt even India has 44V variant of 741, at least cheaply or easy to find.

[exe]

Why do you need 44V?

[rao]

SIR,

A 30V transformer when rectified gives nearly 41V. so it is required 44V for Safety margin.

[Siwastaja]

Use the parametric search of the distributor you are able to use. For example, sorting Digikey for parts rated at least maximum 44V, results in 433 items in stock and normally stocking:
https://www.digikey.fi/products/en/integrated-circuits-ics/linear-amplifiers-instrumentation-op-amps-buffer-amps/687?FV=-8%7C687%2C659%7C100675%2C659%7C103590%2C659%7C143820%2C659%7C143822%2C659%7C143823%2C659%7C143825%2C659%7C143832%2C659%7C143845%2C659%7C143846%2C659%7C143849%2C659%7C143851%2C659%7C143854%2C659%7C143856%2C659%7C155208%2C659%7C155210%2C659%7C184608%2C659%7C184609%2C659%7C184610%2C659%7C184611%2C659%7C184614%2C659%7C208691%2C659%7C208719%2C659%7C215315%2C659%7C228770%2C659%7C228791%2C659%7C228792%2C659%7C233132%2C659%7C238748%2C659%7C249287%2C659%7C249359%2C659%7C257654%2C659%7C261832%2C659%7C267487%2C659%7C267512%2C659%7C267543%2C659%7C287651%2C659%7C287652%2C659%7C295254%2C659%7C295265%2C659%7C297472%2C659%7C305540%2C659%7C305544%2C659%7C66608%2C659%7C69642%2C659%7C69643%2C659%7C69645%2C659%7C69647%2C659%7C74541%2C659%7C74604%2C659%7C74612%2C659%7C74619%2C659%7C94761&quantity=0&ColumnSort=1000011&page=1&stock=1&nstock=1&pageSize=25

The 741 obviously being the cheapest and most universally available. But 44V is the absolute maximum rating, the recommended is just 40V. So this is the caveat with parametric searches, you need to apply some more manual work because you don't know how the sales engineers actually classified the parts exactly.

If the only available "distributor" is a local brick&mortar store or a component dealer on an alley, then why not chat with them, they likely know what they have available and might know at least the basics like voltage ratings of the parts they sell.

Especially when availability is a problem, it's much easier to work with the component dealers to choose the part, than to ask generic advice here.

[xavier60]

Or use a design that will work with common opamps.

[exe]

SIR,

A 30V transformer when rectified gives nearly 41V. so it is required 44V for Safety margin.

Does this account that under no load transformers output higher voltage?

What if power grid voltage is above nominal transformer voltage? Say, transfomer expects 230V, but input is 240V.

I'd suggest use an LDO on opamp rails to lower total supply voltage*. This way the range of available opamps becomes much larger.

*If this is feasible. Without heaving schematics I can't tell if this is going to work.

[Siwastaja]

I'd suggest use an LDO on opamp rails to lower total supply voltage*.

I totally fail to see why you specify an LDO, specifically, when you have significant voltage headroom and want to bring it down. A normal linear regulator works.

LDOs, especially older generation (looking at you, 1117) tend to be compromised compared to traditional normal-drop out linear regulators, for example having peculiar output capacitance requirements that need to be carefully followed to avoid oscillation.

Availability of high-voltage LDOs is on a poor side as well because it's quite a niche use case to require LDO when you have a lot of voltage available. In any case, finally whether a manufacturer thinks the dropout is low enough to be called an LDO is quite arbitrary so setting yourself such meaningless limitation is not fruitful.

[jmelson]

I've used the Linear Technology LTC2057HV in a project requiring about 60 V supply.  It worked quite well.  There is also the LTC2057 without the HV extension that would likely work in your project.  It is a general purpose op-amp but can run off much higher voltages than typical parts.

Jon

[BravoV]

I've used the Linear Technology LTC2057HV in a project requiring about 60 V supply.  It worked quite well.  There is also the LTC2057 without the HV extension that would likely work in your project.  It is a general purpose op-amp but can run off much higher voltages than typical parts.

Jon

Did you read the whole thread ? Or at least where the OP located, his limitation and also budget ($ 0.5) ?

[exe]

I totally fail to see why you specify an LDO, specifically, when you have significant voltage headroom and want to bring it down. A normal linear regulator works.

Sorry, for me LDO == a regulator. Probably incorrect use of the term, but I'm yet to see a modern regulator that would have more than a volt of drop (except modern versions of, say, lm317). Of course old venerable regulators will work too.

[fcb]

LTC2057HV is a good part (others have suggested).

TL072 (from Texas) has a 40V rating, at least one other manufacturer of the TL072 (ST) rates it at 36V.

If cost/availability is a big driver I'd probably roll my own amplifier from discretes, perhaps using MPSA42/92's.

[girishv]

want to construct regulated power supply which should supply 40V with OPAMP and NOT VOLTAGE REG .so i need some general purpose opamp (DIP, T0 package,etc) which could be used for through hole technology.

The members of this forum are kind and helpful. Probably you are better off by sharing more details on your project. I am sure many of them would have done something similar to whatever you are trying to do and have suggestions for you.

[Jwillis]

LT1637 https://www.analog.com/media/en/technical-documentation/data-sheets/1637fd.pdf Single Supply Input Range: – 0.4V to 44V
OPA445 https://www.ti.com/lit/ds/symlink/opa445.pdf?ts=1606675922303  WIDE-POWER  SUPPLY  RANGE  ±10 to ±45  currently running these at 50V in power supply .

[jmelson]

Did you read the whole thread ? Or at least where the OP located, his limitation and also budget ($ 0.5) ?

Yes.  Sometimes, the OP asks for the impossible, and I give a solution that is "possible" but doesn't meet his list of requirements.
There might be ways to do what he needs with ordinary op-amps and a transistor or two, but he really didn't give enough information to know if that could work.

Jon

[schmitt trigger]

I believe we have lost the TS.

He may already be lurking in another forum, to see if they can provide a satisfactory answer to his impossible requirements.

[Kleinstein]

The MC33171/2/4  are  relatively simple OPs specified for 44 V.

The MCP6V51 can be a lower cost alternative to the LTC2057HV - both are AZ OP and thus a little special.

Some audio OPs are also specified for relatively high voltage. Especially the OPA604, that is even OK up to 48 V. However it is not that cheap and relatively fast.

[Zero999]

The MC33171 is a good idea and cheap, but the through hole packages have been discontinued and the original poster wants through hole.

How about the OP07? The trouble is the through hole packages are more expensive than the surface mount one.
https://www.ti.com/lit/ds/symlink/op07c.pdf

SIR,

A 30V transformer when rectified gives nearly 41V. so it is required 44V for Safety margin.

As mentioned above, you need a higher voltage rating than 44V. Transformers output a slightly higher voltage, when operating under light loads and the mains voltage could be on the upper end of the tolerance band.

Please post a schematic.

There are ways to boost the input/output voltage of an op-amp, using cheap transistors.