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What are the differences between single dual supply op-amps?

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sakthivel.eee

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REG:OP-AMP

DEAR ALL,

What are the differences between single supply and dual supply op-amps. What is the major physical difference between them?Construction wise what is the difference?What will happen if i operate single supply op-amp in dual supply and viceversa?

Thanks in advance

Thanks & Regards,
Sakthivel.S
 

dick_freebird

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The significant difference is that the single supply op amp
is designed to work well (or "well enough") with inputs
and/or outputs near the negative (ground, here) rail.
That means follower or composite input stages, an output
that is common-emitter (or common source) rather
than a
follower (Class B or AB) output and stuff like that.

A single supply op amp can probably serve a split-supply
application but the converse is not likely true (otherwise
they would market it that way).
 

LvW

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Re: What are the differences between single dual supply op-a

Quote:
A single supply op amp can probably serve a split-supply
application but the converse is not likely true (otherwise
they would market it that way).


???

Do you really think that a normal - for split supply designed - opamp cannot be operated with single supply ? Of course, each opamp is able to work with a single supply if it is biased properly!
An opamp needs a voltage (that means: a potential difference) between its supply nodes - and it does not matter at all if this voltage is supplied by one or by two sources.
 

dick_freebird

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Re: What are the differences between single dual supply op-a

LvW said:
Quote:
A single supply op amp can probably serve a split-supply
application but the converse is not likely true (otherwise
they would market it that way).


???

Do you really think that a normal - for split supply designed - opamp cannot be operated with single supply ? Of course, each opamp is able to work with a single supply if it is biased properly!
An opamp needs a voltage (that means: a potential difference) between its supply nodes - and it does not matter at all if this voltage is supplied by one or by two sources.


It depends on what you mean by "work". Little things like rated
output current within 1V of the rail, or having the front end not
cut off (likewise) matter to some people.

If you want to make up some "biased properly" constraint on
applications, fine. As long as they're your applications. But
some want specifically the attributes I mentioned and there
aren't always convenient supply choices (like, say, automotive).
 

sakthivel.eee

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Re: What are the differences between single dual supply op-a

HI All,
Construction wise is there any difference?(In physical IC making)? Single supply op-amp can be operated as split supply op-amp.But dual supply needs some external biasing to operate as single supply op-amps.Is that conclusion?My application is automotive...

Thanks in advance.

Sakthi
 

LvW

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Re: What are the differences between single dual supply op-a

sakthivel.eee said:
HI All,
Construction wise is there any difference?(In physical IC making)? Single supply op-amp can be operated as split supply op-amp.But dual supply needs some external biasing to operate as single supply op-amps.Is that conclusion?My application is automotive...
Thanks in advance.
Sakthi

Hi sakthivel.eee,
The difference mostly is in the output stage, which for single supply design should be able to reach ground potential as close as possible. But be aware, that the output can swing - of course - only between (nearly) ground and (nearly) Vsupply.
External biasing is necessary in case you want a bias point in the middle of the output range and your input swings between pos and neg values. This is true for all opamps - whether they are optimized for single supply operation or not!
If your input signal always is positive you don´t need separate external biasing.
Thus, it depends on your application as well as on external constraints (power supply). This is a rather normal situation in engineering business.

Hi dick_freebird,
If you want to make up some "biased properly" constraint on
applications, fine. As long as they're your applications.


I don´t want to "make up" some constraints. They simply exist - dependent on the specific application (see above).
 

sakthivel.eee

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Re: What are the differences between single dual supply op-a

Thanks friends..thanks a lot
 
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