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RRIO OpAmp Recommendation?
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. |
RRIO OpAmp Recommendation?
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 |
RRIO OpAmp Recommendation?
On Fri, 12 Sep 2014 14:16:12 -0400, Phil Hobbs
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. |
RRIO OpAmp Recommendation?
On Fri, 12 Sep 2014 10:58:49 -0700, 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 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 |
RRIO OpAmp Recommendation?
TLV237x
Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com "Jim Thompson" wrote in message ... 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. |
RRIO OpAmp Recommendation?
On Fri, 12 Sep 2014 15:51:37 -0500, "Tim Williams"
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. |
RRIO OpAmp Recommendation?
On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson
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. |
RRIO OpAmp Recommendation?
On 9/13/2014 1:21 PM, John Larkin wrote:
On Fri, 12 Sep 2014 22:52:21 -0400, wrote: On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson 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/vpt...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 |
RRIO OpAmp Recommendation?
On Sat, 13 Sep 2014 19:43:20 -0400, Phil Hobbs
wrote: On 9/13/2014 1:21 PM, John Larkin wrote: On Fri, 12 Sep 2014 22:52:21 -0400, wrote: On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson 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/vpt...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. |
RRIO OpAmp Recommendation?
On Sat, 13 Sep 2014 10:21:49 -0700, John Larkin
wrote: On Fri, 12 Sep 2014 22:52:21 -0400, wrote: On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson 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. I'm paying less than that for the quad. Less than half for the single (though I haven't used any). Yeah, it's a general purpose opamp with nothing special going for it except its cost. It is R-R I/O, which command a premium over others. I can get non R-R opamps from NJR for well under $.10 but they're pretty old-school bipolars. I'm trying to keep my analog rail under 5V, which kinda dictates R-R. |
RRIO OpAmp Recommendation?
On 9/13/2014 8:27 PM, Jim Thompson wrote:
On Sat, 13 Sep 2014 19:43:20 -0400, Phil Hobbs wrote: On 9/13/2014 1:21 PM, John Larkin wrote: On Fri, 12 Sep 2014 22:52:21 -0400, wrote: On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson 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/vpt...077166e&vpid=1 16013415 Cheers Phil Hobbs But not RRIO. ...Jim Thompson Picky, picky. 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 |
RRIO OpAmp Recommendation?
"Phil Hobbs" wrote in message
... Already exists. LM358, $0.09 in quantity 1 from Newark. And it's a dual! ;) http://octopart-clicks.com/click/vpt...077166e&vpid=1 16013415 Speaking of, I've been looking for "single supply" (includes ground) or RRIO chips with higher supply voltage (12V minimum, 16 preferred for reliability). Catch is: needs more GBW than an LM358. Closest I've seen is CA3130, but it seems rather obscure (almost everything CA- is utterly obsolete, though Intersil still seems to be supporting a few). There was one or two from TI or LT that meet or exceed (particularly in offset), but they're no cheaper. Decomp or current feedback would be fine (it's for gain ~ 50, GBW = 25MHz), but both are like hens' teeth, or have way too much GBW (video amps, etc.). Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com |
RRIO OpAmp Recommendation?
On 9/13/2014 11:33 PM, Tim Williams wrote:
"Phil Hobbs" wrote in message ... Already exists. LM358, $0.09 in quantity 1 from Newark. And it's a dual! ;) http://octopart-clicks.com/click/vpt...077166e&vpid=1 16013415 Speaking of, I've been looking for "single supply" (includes ground) or RRIO chips with higher supply voltage (12V minimum, 16 preferred for reliability). Catch is: needs more GBW than an LM358. Closest I've seen is CA3130, but it seems rather obscure (almost everything CA- is utterly obsolete, though Intersil still seems to be supporting a few). I remember those. The CA3140 was more or less the same part, but with a bipolar totem-pole output stage. The CA3100 was magic back in about 1980--it was the only amp we could find that could handle multiple channel PSK data in a 3-MHz bandwidth with acceptable intermod. TI makes a bunch of quite reasonable higher-voltage op amps, e.g. the OPA188/2188/4188 chopamps. Cheers Phil Hobbs There was one or two from TI or LT that meet or exceed (particularly in offset), but they're no cheaper. Decomp or current feedback would be fine (it's for gain ~ 50, GBW = 25MHz), but both are like hens' teeth, or have way too much GBW (video amps, etc.). Tim -- 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 |
RRIO OpAmp Recommendation?
"Phil Hobbs" wrote in message ... On 9/13/2014 1:21 PM, John Larkin wrote: On Fri, 12 Sep 2014 22:52:21 -0400, wrote: On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson 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/vpt...077166e&vpid=1 16013415 Cheers Phil Hobbs But the LM358 doesn't use any bias, and so there is crossover distortion at the mid point if used in a linear application such as audio. Maybe that's not an issue for other applications? -Bill --- news://freenews.netfront.net/ - complaints: --- |
RRIO OpAmp Recommendation?
On 9/14/2014 11:55 PM, Bill Bowden wrote:
"Phil Hobbs" wrote in message ... On 9/13/2014 1:21 PM, John Larkin wrote: On Fri, 12 Sep 2014 22:52:21 -0400, wrote: On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson 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/vpt...077166e&vpid=1 16013415 Cheers Phil Hobbs But the LM358 doesn't use any bias, and so there is crossover distortion at the mid point if used in a linear application such as audio. Maybe that's not an issue for other applications? -Bill For nine cents in onesies, he expects perfection. An arrant varlet, forsooth. ;) LM358s and 324s are occasionally useful, but usually in unipolar applications, true. A figure of merit for a given design is how crappy an amplifier you can use and have it still work well. 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 |
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