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Which opamps generate their own internal Vref?

Started by merlinb, August 19, 2012, 09:30:58 AM

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merlinb

August 19, 2012, 09:30:58 AM
Can anyone tell me some opamps (or opamp-like devices) that generate their own internal Vref?
In other words, devices that can run off a single rail supply yet have ground-referenced inputs, or which only require a coupling cap to feed the signal in- no Vref divider required?

The LM386 is one example, but are there others?

PRR

#1
August 20, 2012, 01:42:50 AM
LM10
LM387
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greaser_au

#2
August 20, 2012, 08:54:02 AM Last Edit: August 20, 2012, 09:04:29 AM by greaser_au
I said: Quad  device: LM324  

but it appears that while it is designed for single supply operation it still needs   Vcc/2 biasing... sorry  :(

david

puretube

#3
August 20, 2012, 01:32:46 PM
Not opamp or -like,
but amplifies and inverts and idles its output midway*:
CMOS-Inverter...

*(as long as there is a DC-path from out-to-in...)

R.G.

#4
August 20, 2012, 01:51:45 PM
hmm...
Dirty tricks, advanced class. Paint two equal lengths of conductive paint on the bottom of the IC in black, going from V+ to V- and stopping in the middle at + input.

Reverse engineer that one.   :icon_lol:
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

puretube

#5
August 20, 2012, 02:05:23 PM
Quote from: R.G. on August 20, 2012, 01:51:45 PM
hmm...
Dirty tricks, advanced class. Paint two equal lengths of conductive paint on the bottom of the IC in black, going from V+ to V- and stopping in the middle at + input.

Reverse engineer that one.   :icon_lol:

...and now the "noiseless biasing" version?
(with series-R from midpoint to + input)

R.G.

#6
August 20, 2012, 02:45:04 PM
Quote from: puretube on August 20, 2012, 02:05:23 PM
Quote from: R.G. on August 20, 2012, 01:51:45 PM
hmm...
Dirty tricks, advanced class. Paint two equal lengths of conductive paint on the bottom of the IC in black, going from V+ to V- and stopping in the middle at + input.

Reverse engineer that one.   :icon_lol:

...and now the "noiseless biasing" version?
(with series-R from midpoint to + input)
The only problem is finding electrolytic capacitor paint for bypassing the bias point.    :icon_biggrin:
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

PRR

#8
August 20, 2012, 05:15:27 PM
TDA2003 (and family)
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Cliff Schecht

#9
August 20, 2012, 05:40:27 PM
A TL431 gives you an op amp and accurate reference voltage to develop whatever reference supply you want. It's more accurate than just using resistor dividers and can supply a lot of current (~100mA continuous) in a small package (TO-92). Maybe not a single part solution, but a damn fine 3-4 part solution..

soggybag

#11
August 21, 2012, 12:50:37 AM
Not sure but, LM386 might qualify here.

puretube

#12
January 12, 2013, 07:04:21 PM
Quote from: puretube on August 20, 2012, 06:26:37 PM
o.k., then:
...
or amp-wise:
http://www.nxp.com/documents/data_sheet/TDA7052.pdf
...

It`s a pity they are being discontinued...  :icon_wink:

Kesh

#13
January 12, 2013, 09:48:55 PM
I kind of feel more confident doing it myself.
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