Forums

RRIO OpAmp Recommendation?

Started by Jim Thompson September 12, 2014
I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a
current mirror.

What would you guys in the discrete world recommend as being
well-behaved, no peculiarities, etc?  (And readily available ;-)

Thanks!
		
                                        ...Jim Thompson
-- 
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
On 09/12/2014 01:58 PM, Jim Thompson wrote:
> I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a > current mirror. > > What would you guys in the discrete world recommend as being > well-behaved, no peculiarities, etc? (And readily available ;-) > > Thanks! > > ...Jim Thompson >
I'm a fan of the AD8605. It has fast local feedback wrapped round the output stage, so that its output impedance doesn't climb nearly as fast as most RROs. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
On Fri, 12 Sep 2014 14:16:12 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 09/12/2014 01:58 PM, Jim Thompson wrote: >> I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a >> current mirror. >> >> What would you guys in the discrete world recommend as being >> well-behaved, no peculiarities, etc? (And readily available ;-) >> >> Thanks! >> >> ...Jim Thompson >> > >I'm a fan of the AD8605. It has fast local feedback wrapped round the >output stage, so that its output impedance doesn't climb nearly as fast >as most RROs. > >Cheers > >Phil Hobbs
Thanks, Phil! That's how I design them on-chip... local feedback cures that transconductance nastiness. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a >current mirror. > >What would you guys in the discrete world recommend as being >well-behaved, no peculiarities, etc? (And readily available ;-) > >Thanks! > > ...Jim Thompson
I use a lot of LM7301s, but they are 32 volt parts and cost more than lower voltage stuff. LMV931 is OK. AD8565 isn't cheap, but it's a remarkable part. 16 volts RRIO, 250 mA peak out, comes off the rails clean in a microsecond, c-load stable. -- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
TLV237x

Tim

-- 
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com

"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote 
in message news:bsc61a9h61998bfuhie8ag7bjmhdp2dlfl@4ax.com...
>I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a > current mirror. > > What would you guys in the discrete world recommend as being > well-behaved, no peculiarities, etc? (And readily available ;-) > > Thanks! > > ...Jim Thompson > -- > | James E.Thompson | mens | > | Analog Innovations | et | > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > | San Tan Valley, AZ 85142 Skype: skypeanalog | | > | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | > | E-mail Icon at http://www.analog-innovations.com | 1962 | > > I love to cook with wine. Sometimes I even put it in the food.
On Fri, 12 Sep 2014 15:51:37 -0500, "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

>TLV237x > >Tim
Thanks for all the tips. I sent the client (in Taiwan) a solution using the AD8605 that Phil suggested (and I could find a model for). I'll provide him also with all the alternates... this is a slow loop so I think any will do. Thanks again. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a >current mirror.
What specs?
>What would you guys in the discrete world recommend as being >well-behaved, no peculiarities, etc? (And readily available ;-)
I've been using the MicroChip MCP6294, mainly because they're cheap but the specs matter.
On Fri, 12 Sep 2014 22:52:21 -0400, krw@attt.bizz wrote:

>On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a >>current mirror. > >What specs? > >>What would you guys in the discrete world recommend as being >>well-behaved, no peculiarities, etc? (And readily available ;-) > >I've been using the MicroChip MCP6294, mainly because they're cheap >but the specs matter.
That looks OK for non-critical stuff. The single MCP6291 in SOT23 is around 40 cents in quantity. (I like singles, usually.) Somewhere there ought to be a really cheap workhorse opamp, ten cents maybe. -- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On 9/13/2014 1:21 PM, John Larkin wrote:
> On Fri, 12 Sep 2014 22:52:21 -0400, krw@attt.bizz wrote: > >> On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>> I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a >>> current mirror. >> >> What specs? >> >>> What would you guys in the discrete world recommend as being >>> well-behaved, no peculiarities, etc? (And readily available ;-) >> >> I've been using the MicroChip MCP6294, mainly because they're cheap >> but the specs matter. > > That looks OK for non-critical stuff. The single MCP6291 in SOT23 is > around 40 cents in quantity. (I like singles, usually.) Somewhere > there ought to be a really cheap workhorse opamp, ten cents maybe. > >
Already exists. LM358, $0.09 in quantity 1 from Newark. And it's a dual! ;) http://octopart-clicks.com/click/vptrack?ak=68b25f31&sig=077166e&vpid=1 16013415 Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
On Sat, 13 Sep 2014 19:43:20 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 9/13/2014 1:21 PM, John Larkin wrote: >> On Fri, 12 Sep 2014 22:52:21 -0400, krw@attt.bizz wrote: >> >>> On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson >>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>> I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a >>>> current mirror. >>> >>> What specs? >>> >>>> What would you guys in the discrete world recommend as being >>>> well-behaved, no peculiarities, etc? (And readily available ;-) >>> >>> I've been using the MicroChip MCP6294, mainly because they're cheap >>> but the specs matter. >> >> That looks OK for non-critical stuff. The single MCP6291 in SOT23 is >> around 40 cents in quantity. (I like singles, usually.) Somewhere >> there ought to be a really cheap workhorse opamp, ten cents maybe. >> >> > >Already exists. LM358, $0.09 in quantity 1 from Newark. And it's a >dual! ;) > >http://octopart-clicks.com/click/vptrack?ak=68b25f31&sig=077166e&vpid=1 >16013415 > >Cheers > >Phil Hobbs
But not RRIO. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.