Single Supply Op-Amp

[Ken McDonald]

Can someone recommend a single supply op-amp with better specs than an
LM358?

Thanks,

Ken McDonald

 

[CFoley1064]

Subject: Single Supply Op-Amp
From: "Ken McDonald" sorry.no@email.com
Date: 10/30/2004 11:26 AM Central Daylight Time
Message-id: <lhPgd.1977$vH5.1958@fe1.columbus.rr.com

Can someone recommend a single supply op-amp with better specs than an
LM358?

Thanks,

Ken McDonald

Lots of them.. What do you need?

Chris

 

[Repzak]

"Ken McDonald" <sorry.no@email.com> skrev i en meddelelse
news:lhPgd.1977$vH5.1958@fe1.columbus.rr.com...

Can someone recommend a single supply op-amp with better specs than an
LM358?

What are you needs ?

which application ?

Rail to Rail ?

Kasper

 

[Jamie]

http://www.analog.com/en/prod/0%2C2877%2CAD8057%2C00.html
that is an example.
but its not the DIP package.
LM318 is a little better in Band Pass but
requires a min of 10 Vcc. but can handle
40 Vcc.
etc..


Ken McDonald wrote:

Can someone recommend a single supply op-amp with better specs than an
LM358?

Thanks,

Ken McDonald

 

[Ken McDonald]

"Repzak" <repzak@GEDhotmail.com> wrote in message
news:4183e595$0$33733$14726298@news.sunsite.dk...

"Ken McDonald" <sorry.no@email.com> skrev i en meddelelse
news:lhPgd.1977$vH5.1958@fe1.columbus.rr.com...
Can someone recommend a single supply op-amp with better specs than an
LM358?

What are you needs ?

I guess I'm looking for a single supply dual general purpose op-amp that has
higher gain and higher slew rate than an LM358. Something newer I guess.

which application ?

I'm working on an infrared receiver right now, but am always throwing some
kind of amplifier circuit together.

Rail to Rail ?

Rail to Rail would be nice, but definitely want the output to go to ground.

Ken

Kasper

 

[CFoley1064]

Subject: Re: Single Supply Op-Amp
From: "Ken McDonald" sorry.no@email.com
Date: 10/30/2004 2:10 PM Central Daylight Time
Message-id: <lGRgd.77085$5v2.32081@fe2.columbus.rr.com


"Repzak" <repzak@GEDhotmail.com> wrote in message
news:4183e595$0$33733$14726298@news.sunsite.dk...

"Ken McDonald" <sorry.no@email.com> skrev i en meddelelse
news:lhPgd.1977$vH5.1958@fe1.columbus.rr.com...
Can someone recommend a single supply op-amp with better specs than an
LM358?

What are you needs ?

I guess I'm looking for a single supply dual general purpose op-amp that has
higher gain and higher slew rate than an LM358. Something newer I guess.


which application ?

I'm working on an infrared receiver right now, but am always throwing some
kind of amplifier circuit together.


Rail to Rail ?

Rail to Rail would be nice, but definitely want the output to go to ground.

Ken


Kasper

Hi, Ken. Usually, the LM358/LM324 are looked at as starting points. They're
popular because of the balance of features at a dirt-cheap price.

I'm hearing:
Single supply dual op amp
Higher gain than LM358 (GBW = 0.7 MHz)
Higher slew rate (SR = 0.3V/us)
Other than that, everything else at least as good as an LM358.

Of course, you'll have to pay more. One good choice for a "super LM358" is the
OP292, available from Analog Devices. The non-improvements include:

Minimum single supply = 4.5V
More expensive: DigiKey Prices
LM358NNS-ND $0.54 ea.
OP292GS-ND $3.02 ea.

Everything else is a plus. Check it out:

http://www.analog.com/UploadedFiles/Data_Sheets/882565314OP292_492_b.pdf


Good luck
Chris

 

[Pooh Bear]

Ken McDonald wrote:

Can someone recommend a single supply op-amp with better specs than an
LM358?

You don't *have* to use so called 'single supply' op-amps for single
supply applications.

It depends on the application.

So called 'single supply' op-amps usually include ground in the input
common mode spec - that's the point of them.

AC coupled signals as per the OP's example don't need this.

What's the application - then a sensible suggestion can be made.


Graham

 

[Pooh Bear]

Ken McDonald wrote:

Rail to Rail would be nice, but definitely want the output to go to ground.

No op-amp that I know of has an output that actually goes to *ground*. For the
simple reason that there will be an active device between the output terminal
and the ground ( V- ) terminal.

CMOS types may typically get within a few tens of millivolts.

If we knew more about what you're doing it would help. Of course the output can
go to ground if you're working with split supplies.


Graham

 

[Country Loon]

"Andrew Holme" <andrew@nospam.com> wrote in message
news:clpb9m$j4r$1$8302bc10@news.demon.co.uk...

Love a Sheep wrote:
Hi, I need an op-amp configured so that it acts in differential mode
(to subtract two signals) but with a single supply. It can be
ac-coupled.

View in a fixed width font
|| ___ ___
-||--|___|-----------+-----|___|---+
|| | |
| |
| |
VCC | VCC |
| | | |
.-. | | |
R1 | | | | |
| | | |\| |
'-' +----|-\ |
|| ___ | | >-----+-----
-||--|___|-+--------------|+/
|| | |/|
.-. |
| | |
R2 | | |
'-' |
| |
| |
=== ===
GND GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

R1 and R2 are equivalent to (R1 || R2) returned to half rail.

I have it now! A weird font gives me the picture. (MS Mincho!) However, I do
not know what the series resistor feeding the supply splitter is? I figured
out most of the circuit myself but not this resistor.
My guess is that the Thevin equivalent of R1 and R2 (ie R1 in parallel with
R2) must be the same value as the feedback resistor to the - input and the
series resistor is the onther one.

Thanks

Tom

 

[Winfield Hill]

Bill Sloman wrote...

Farnell stocked the LT1013 and LT1014 the last time I looked,
but the LT1006 was a bit harder to get hold of.

DigiKey stocks them. The Linear Technology version is expensive,
e.g. LT1013CN8 at $4.25 each, but the TI LT1013CP version is more
reasonably priced, at $1.40. Both feature a nice low 300uV max
offset voltage. As far as the LT1006 single opamp is concerned,
DigiKey has this LTC-only part, $2.88 each. It's getting scarce.


--
Thanks,
- Win

(email: use hill_at_rowland-dotties-org for now)

 

[Winfield Hill]

Winfield Hill wrote...

Bill Sloman wrote...

Farnell stocked the LT1013 and LT1014 the last time I looked,
but the LT1006 was a bit harder to get hold of.

DigiKey stocks them. The Linear Technology version is expensive,
e.g. LT1013CN8 at $4.25 each, but the TI LT1013CP version is more
reasonably priced, at $1.40. Both feature a nice low 300uV max
offset voltage.

I should add that the LT1013 is a favorite of mine, over the LM358.
And in the cases where four opamps are handy, the LT1014 of course.
For cost-sensitive designs, there's TI's LT1013DD, $0.43 qty 1k,
with 800uV max input offset.

Besides a low offset voltage, these chips have circuitry to prevent
phase reversal (* see below). There's more, as LTC says, "Although
supply current is only 350mA per amplifier, a new output stage
design sources and sinks in excess of 20mA of load current, while
retaining high voltage gain. ... Crossover distortion, so apparent
on previous single-supply designs, is eliminated."

* "At the input, the driving signal can fall below 0V— inadvertently
or on a transient basis. If the input is more than a few hundred
millivolts below ground, two distinct problems can occur on previous
single supply designs, such as the LM124, LM158, OP-20, OP-21, OP-220,
OP-221, OP-420:
a) When the input is more than a diode drop below ground, unlimited
current will flow from the substrate (V – terminal) to the input.
This can destroy the unit. On the LT1013/LT1014, the 400W resistors,
in series with the input (see Schematic Diagram), protect the devices
even when the input is 5V below ground.
b) When the input is more than 400mV below ground (at 25°C), the input
stage saturates (transistors Q3 and Q4) and phase reversal occurs at
the output. This can cause lock-up in servo systems. Due to a unique
phase reversal protection circuitry (Q21, Q22, Q27, Q28), the LT1013/
LT1014’s outputs do not reverse, as illustrated below ..."


--
Thanks,
- Win

 

[ChrisGibboGibson]

"legg" <legg@nospam.magma.ca> wrote in message
news:46c2o098pjmdj3eu9ri58fas5l0qd52b3h@4ax.com...
On Thu, 28 Oct 2004 13:32:08 -0400, "Tam/WB2TT"
t-tammaru@c0mca$t.net> wrote:


"Love a Sheep" <sheepshaggerx@yahoo.co.uk> wrote in message
news:264c4ea4.0410271421.5dd99fc6@posting.google.com...
Hi, I need an op-amp configured so that it acts in differential mode
(to subtract two signals) but with a single supply. It can be
ac-coupled.
I know how to do this with a dual power supply but I am unsure how to
do this with teh singel supply.

Thanks

If you use an op amp where the common mode range extends to 0, and the
input
voltage is small enough, you don't need to do any of these things that
people are talking about.

Tam

.....unless the expected resulting output would have to go negative
(ie any AC ground-referenced input signal)

sheesh

RL

OK, you got me. I don't remember the detail, but when I used an op amp like
that, I think the input signal was DC coupled and never went below some
VCE(sat). Now if we knew what the DC level of his two input signals is (or
can be made), the whole discussion might be moot.

Now this is a point that always got me.

Look at the specs of op amps. Assume a perfect one. Both inputs at *exactly*
the same voltage. What's the output?

According to the specs and text books it's zero. But is it? Is it not halfway
between V+ and V- ? Which may be far removed from zero.

This seems cause great fun in simulators.

Gibbo

 

[Watson A.Name - \"Watt Su]

"Tim Shoppa" <shoppa@trailing-edge.com> wrote in message
news:bec993c8.0411030856.434f13f@posting.google.com...

Winfield Hill <whill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:<cm7vqe0lg9@drn.newsguy.com>...
Bill Sloman wrote...

Farnell stocked the LT1013 and LT1014 the last time I looked,
but the LT1006 was a bit harder to get hold of.

DigiKey stocks them. The Linear Technology version is expensive,
e.g. LT1013CN8 at $4.25 each, but the TI LT1013CP version is more
reasonably priced, at $1.40. Both feature a nice low 300uV max
offset voltage. As far as the LT1006 single opamp is concerned,
DigiKey has this LTC-only part, $2.88 each. It's getting scarce.

TI has some interesting parts if you know that you'll be working with
5V Vcc:

cheaper than the LT1013 is the LMV358

more expensive than the LT1013 is the TLV2472

I don't understand what in their manufacture limits these parts to
5V operation.

I don't understand why TI needs to have pages and pages of opamps in the
mouser, etc. catalogs. Why so many almost identical parts..

> Tim.

 

[RMC]

The absolute maximum voltage spec for ICs (i.e., the 5V for these op amps)
is a function
of the process geometry -- the smaller the device geometries, the lower the
breakdown voltages.

A good rule-of-thumb for .5 micron and smaller geometry processes is that
the rated operating
voltage is 10x the process geometry, thus

0.13u = 1.1V
0.18u = 1.8V
..25u = 2.5V
..5u, .6u = 5V

Sometimes there are "think oxide" devices on a process, so you'll see
converters with a 2.5V analog supply
and a 3.3V digital supply - the thick oxide devices are used in the digital
I/O section only for the logic interface
to the outside wolrd and internally the logic runs at 2.5V.

As for the pages and pages of op amps, there are differences in ft; slew
rate; input offset voltage and current;
input bias current; input common mode voltage; output voltage swing and
output current; ability to drive a
capacitive load; input noise voltage and input noise current, and of course,
supply voltage and supply current.
Apply these differences to more than 20 years of op amp design and you can
see why there are pages and pages of parts!

Bob Clarke

PS: Analog Devices (my employer) also has lots of good op amps.



"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:10on12dskdkscb3@corp.supernews.com...

"Tim Shoppa" <shoppa@trailing-edge.com> wrote in message
news:bec993c8.0411030856.434f13f@posting.google.com...
Winfield Hill <whill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:<cm7vqe0lg9@drn.newsguy.com>...
Bill Sloman wrote...

Farnell stocked the LT1013 and LT1014 the last time I looked,
but the LT1006 was a bit harder to get hold of.

DigiKey stocks them. The Linear Technology version is expensive,
e.g. LT1013CN8 at $4.25 each, but the TI LT1013CP version is more
reasonably priced, at $1.40. Both feature a nice low 300uV max
offset voltage. As far as the LT1006 single opamp is concerned,
DigiKey has this LTC-only part, $2.88 each. It's getting scarce.

TI has some interesting parts if you know that you'll be working with
5V Vcc:

cheaper than the LT1013 is the LMV358

more expensive than the LT1013 is the TLV2472

I don't understand what in their manufacture limits these parts to
5V operation.

I don't understand why TI needs to have pages and pages of opamps in the
mouser, etc. catalogs. Why so many almost identical parts..

Tim.