TL081 vs TL071

  • Thread starter Michael A. Covington
  • Start date
M

Michael A. Covington

Guest
What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18 nv/sqrt(Hz)), as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).

I've been using them both as general-purpose op-amps for a long time and
haven't noticed any difference between them. Are they generally well
regarded? What do people prefer as an all-purpose, default-choice op-amp
these days (in place of the old 741, which I always thought was too noisy)?
 
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message
news:411ef6ba$1@mustang.speedfactory.net...
What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18
nv/sqrt(Hz)), as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).

I've been using them both as general-purpose op-amps for a long time
and
haven't noticed any difference between them. Are they generally well
regarded? What do people prefer as an all-purpose, default-choice
op-amp
these days (in place of the old 741, which I always thought was too
noisy)?
Click to expand...
5532 series for audio apps? The TL082 was sold by Rat Shack but the
package would come with either that or a LF353. I guess they were
interchangeable. I would not use a 741 for decent Hi-Fi audio apps.
 
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message
news:411ef6ba$1@mustang.speedfactory.net...
What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18 nv/sqrt(Hz)),
as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).
Click to expand...
To make matters even murkier, if you look at the circuit diagrams on the
data sheets, they're identical! But identical circuitry doesn't necessarily
mean that the processing is exactly the same, that the size of the
transistors is identical, ...

But they do look very similar. I've been told that there are circuits in
which one will work and not the other. I don't choose to find out for
myself -- see below.


I've been using them both as general-purpose op-amps for a long time and
haven't noticed any difference between them. Are they generally well
regarded? What do people prefer as an all-purpose, default-choice op-amp
these days (in place of the old 741, which I always thought was too
noisy)?
Click to expand...
I bought lots of 100 NE5534 single and NE5532 dual op amps on eBay to use in
my own audio designs. There are better choices but at $4-8 each instead of
40-80 cents. The 741 isn't worth anything above a few kilohertz and even
then the noise and offset specs are lousy. But they're cheap.

Norm
 
Thanks. I should add that I'm not looking for the ideal audio amp -- I have
others for that. Rather, I'm trying to settle on something better than the
741 as a cheap, abundant op-amp for a wide range of non-critical uses. Part
of the appeal of the TL081/2/4 (or TL071/2/4) is that it's easy to remember
the numbers (single, dual, quad).
 
"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> wrote in message
news:10huu06mbocnae8@corp.supernews.com...
i could be wrong but i think the 71 is a bipolar input type
and the 81 is the cmos high gain input with a much better
linearity to it.
Click to expand...
They seem to have the same circuit diagram.
 
i could be wrong but i think the 71 is a bipolar input type
and the 81 is the cmos high gain input with a much better
linearity to it.



Michael A. Covington wrote:

What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18 nv/sqrt(Hz)), as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).

I've been using them both as general-purpose op-amps for a long time and
haven't noticed any difference between them. Are they generally well
regarded? What do people prefer as an all-purpose, default-choice op-amp
these days (in place of the old 741, which I always thought was too noisy)?
Click to expand...
 
"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> wrote in message
news:10huu06mbocnae8@corp.supernews.com...
i could be wrong but i think the 71 is a bipolar input type
and the 81 is the cmos high gain input with a much better
linearity to it.
Click to expand...
They are all fet input.

The 61 was low current (or low offset, I forget..) the 71 was low noise, and
the 81 was low cost.

Same for 62/72/82 and 64/74/84
 
"Dave VanHorn" <dvanhorn@cedar.net> wrote in message
news:u4udnfJlWvDkfoLcRVn-pw@comcast.com...
They are all fet input.

The 61 was low current (or low offset, I forget..) the 71 was low noise,
and the 81 was low cost.

Same for 62/72/82 and 64/74/84
Click to expand...
Yes. But as the OP noted, and as was noted in an earlier thread on exactly
the same topic, the specs for the 7x and 8x are virtually identical these
days. "Low noise" and "low cost" seem to no longer be differentiators.

My own theory - unsupported by any evidence other than the existence of
multiple part numbers for seemingly the same part, along with historical
anecdotes about the parts behaving differently - is that they used to be
different, but at some point the mfrs decided that the "low noise" process
had gotten cheap enough or the "low cost" process had gotten quiet enough
that they just started using the same innards for both.

Again, that's just a theory; would be nice to hear from someone at TI.
 
My own theory - unsupported by any evidence other than the existence of
multiple part numbers for seemingly the same part, along with historical
anecdotes about the parts behaving differently - is that they used to be
different, but at some point the mfrs decided that the "low noise" process
had gotten cheap enough or the "low cost" process had gotten quiet enough
that they just started using the same innards for both.

Again, that's just a theory; would be nice to hear from someone at TI.
Click to expand...
I need to look at my old data books! My dim recollection is that when I
settled on the TL081 back in the 1980s, it was quite distinct from the
TL071. (Maybe it just cost less.) But Horowitz and Hill 1989 already show
the same numbers for the specs of both chips (actually appreciably less
offset on the '81; no visible advantage to the '71 though they tag it "low
noise").
 
"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> wrote in message
news:10hvn1hh85u2k40@corp.supernews.com...
yes, they have the same lay out, they are pin for pin compatible.
but that does not mean they are the same in electrical ratings
like gain, BandWidth etc.
Click to expand...
I mean the schematic of the chip itself is published in the data sheets and
is the same for both. Also, the numbers that indicate performance are
practically identical.
 
yes, they have the same lay out, they are pin for pin compatible.
but that does not mean they are the same in electrical ratings
like gain, BandWidth etc.


Michael A. Covington wrote:

"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> wrote in message
news:10huu06mbocnae8@corp.supernews.com...

i could be wrong but i think the 71 is a bipolar input type
and the 81 is the cmos high gain input with a much better
linearity to it.


They seem to have the same circuit diagram.
Click to expand...
 
"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:cfosg0$7k7$0$216.39.172.65@theriver.com...
"Dave VanHorn" <dvanhorn@cedar.net> wrote in message
news:u4udnfJlWvDkfoLcRVn-pw@comcast.com...
They are all fet input.

The 61 was low current (or low offset, I forget..) the 71 was low
noise,
and the 81 was low cost.

Same for 62/72/82 and 64/74/84

Yes. But as the OP noted, and as was noted in an earlier thread on
exactly
the same topic, the specs for the 7x and 8x are virtually identical
these
days. "Low noise" and "low cost" seem to no longer be
differentiators.

My own theory - unsupported by any evidence other than the existence
of
multiple part numbers for seemingly the same part, along with
historical
anecdotes about the parts behaving differently - is that they used to
be
different, but at some point the mfrs decided that the "low noise"
process
had gotten cheap enough or the "low cost" process had gotten quiet
enough
that they just started using the same innards for both.

Again, that's just a theory; would be nice to hear from someone at TI.
Click to expand...
Well, TI has pages and pages of opamps in the catalogs of the likes of
Digi-key and Mouser. Makes choosing an appropriate opamp totally
bewildering.

And that's from just one manufacturer!
 
Yes. But as the OP noted, and as was noted in an earlier thread on
exactly
the same topic, the specs for the 7x and 8x are virtually identical
these days. "Low noise" and "low cost" seem to no longer be
differentiators.
Click to expand...
This was originally done back in the late 70's or early 80's and that was
the official word from TI.
 
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message
news:4120068a$1@mustang.speedfactory.net...
I mean the schematic of the chip itself is published in the data sheets
and
is the same for both. Also, the numbers that indicate performance are
practically identical.
Click to expand...
I've just found my copy of "The BiFET Design Manual" 2nd Ed. 1982 and
I'll take a look later. I like the range and also the M'Rola MC33079P for
audio filter applications. I think the MC33079 has gone obsolete now.


--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.
 
"Michael A. Covington" (look@ai.uga.edu.for.address) writes:
What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18 nv/sqrt(Hz)), as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).

It took a bit of digging, but I pulled out the brochure TI sent out when
Click to expand...
these devices were just introduced, dated 1977. Well, I knew where it was,
but the specific box was under some others.

TL081 = 47nV
TL071 = 18nV

input offset voltage
TL081 = 15 to 20mV
TL071 = 10 to 13mV

input offset current
TL082 = 0.2 to 5nA
TL071 = .05 to 2nA

Icc max
TL082 = 2.8mA
TL071 = 2.5mA

Prices in 100 unit quantities
TL082 = .33
TL071 = .47

This is from their comparison chart. I've not dug into the separate
data sheets later in the brochure. The internal diagrams look the same,
but not all values are given.

It doesn't seem to say much about why the two devices differ, ie if
one is a hand selected from the larger pool.

There clearly was a stated difference from the starting gate, but who
knows how long that held true.

Michael



I've been using them both as general-purpose op-amps for a long time and
haven't noticed any difference between them. Are they generally well
regarded? What do people prefer as an all-purpose, default-choice op-amp
these days (in place of the old 741, which I always thought was too noisy)?
Click to expand...
 
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message news:<411f7a6e$1@mustang.speedfactory.net>...
Thanks. I should add that I'm not looking for the ideal audio amp -- I have
others for that. Rather, I'm trying to settle on something better than the
741 as a cheap, abundant op-amp for a wide range of non-critical uses.
Click to expand...
The 741 has its problems but by definition it's the all-around jellybean
part :).

See the thread from January of this year "Singing the praises of the LM324",
too. It's often-villified for crossover distortion (there *are* workarounds)
but it works very well for DC-ish applications from rail to rail.

Tim.
 
See the thread from January of this year "Singing the praises of the
LM324",
too. It's often-villified for crossover distortion (there *are*
workarounds)
but it works very well for DC-ish applications from rail to rail.

Tim.
Click to expand...
Well, the Xover distortion can be a really hideous nasty surprise, if you
don't know about it in advance.
 
"Michael Black" <et472@FreeNet.Carleton.CA> wrote in message
news:cfr208$vb$1@freenet9.carleton.ca...
"Michael A. Covington" (look@ai.uga.edu.for.address) writes:
What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18 nv/sqrt(Hz)),
as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).

It took a bit of digging, but I pulled out the brochure TI sent out when
these devices were just introduced, dated 1977. Well, I knew where it
was,
but the specific box was under some others.

TL081 = 47nV
TL071 = 18nV
Click to expand...
AHA! Nowadays both are specified as 18 nV/sqrt(Hz).

I'll bet nowadays they are the same chip! Originally they weren't.
 
"Michael A. Covington" (look@ai.uga.edu.for.address) writes:
"Michael Black" <et472@FreeNet.Carleton.CA> wrote in message
news:cfr208$vb$1@freenet9.carleton.ca...

"Michael A. Covington" (look@ai.uga.edu.for.address) writes:
What is the difference between these op-amps? The latter is billed as
"low-noise" but they have the same noise specification (18 nv/sqrt(Hz)),
as
well as nearly all the same other specifications ('81 has less offset
error). And the same price (48 cents).

It took a bit of digging, but I pulled out the brochure TI sent out when
these devices were just introduced, dated 1977. Well, I knew where it
was,
but the specific box was under some others.

TL081 = 47nV
TL071 = 18nV

AHA! Nowadays both are specified as 18 nV/sqrt(Hz).

I'll bet nowadays they are the same chip! Originally they weren't.



Of course, that now leads to the question of when this occurred. Do
Click to expand...
we all have the low noise ones in our junkboxes, or is a relatively recent
change?

I don't have a complete sequence of TI literature (or any company's literature
for that matter) in order to check year by year, or even decade by decade.

Michael
 
TL081 = 47nV
TL071 = 18nV

AHA! Nowadays both are specified as 18 nV/sqrt(Hz).

I'll bet nowadays they are the same chip! Originally they weren't.

Of course, that now leads to the question of when this occurred. Do
we all have the low noise ones in our junkboxes, or is a relatively recent
change?
Click to expand...
The chart in The Art of Electronics, 1989, lists them both as 18 nV/sqrt(Hz)
but describes the '71 as "low noise." Does anybody have the earlier edition
of The Art of Electronics?
 
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