In case that earlier answer wasn't clear enough, look at =46igure 19.2 in the family user's guide where they talk about the high resolution generator. It can multiply by 8 or by 16. And start reading the text around there and below. I think you will see what is going on. (Atmel does it on some of their parts, too.)
See also:
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Actually, that's the balanced modulator version. The MC1495 - no longer made - had the extra circuitry to make it a more or less accurate multiplier, which slowed it down a bit.
It wasn't anything like as good as the Analog Devices parts are now, and it was a bit if pig to use - like the MC4024/MC4044 parts for which Jim Thompson also admits responsibility - but it was cheap, as it had to be to sell at all against the much better Analog Devices and Burr-Brown parts.
-- Bill Sloman, Nijmegen
This is another one of your zero context questions. Sounds like you're working on a amplifier with uC controlled gain, and some crazy demod/mod scheme with the couple hundred kiloHz control frequency?
on a amplifier with uC controlled gain, and some crazy demod/mod scheme with the couple hundred kiloHz control frequency?
Like, should be done OTHER than with an optically controlled resistor ?:-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| 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.
Give a non-isolated example that does absolutely everything you need, then we'll figure out how to do it, isolated.
I'm sick to death of weaseling.
RL
Yeah, one is a "tiny" 400W boost. I cheated, though, and it's four-phase. ;-) Most of the others are in the 15-20W class.
Or just replacing a pot with a plasic shaft, to go vroom vroom.
When you see resistance-controlled interface, you have to think 'OLD'. You get the gold star if you can do it some other way.
A resistor seldom has to do everything:
- It may be polarized, in it's place.
- It may be used with a fixed voltage - actually modulating branch current.
- It may be used at a fixed current - actually modulating a node voltage.
If a variable resistor did work, then there were acceptable limits of linearity, resolution, minimum and maximum compliance values that would be expressed and passed on.
If it didn't actually work, then there's little point in promoting a substitute that attempts the same degree of basic malfunction.
I hope this isn't another frigging lamp dimmer, with power factor correction. These will likely never see significant North American manufacture, no matter what brand name gets stamped on them.
RL
The above describes quite accurately what's needed. Of course I can't post a schematic.
Only if it costs less.
Yes, it can be.
Unfortunately it can't :-(
I wish, but no.
This was stated in my original post: substitute that attempts the same degree of basic malfunction.
You may be very mistaken there :-)
-- Regards, Joerg http://www.analogconsultants.com/
Amazing! Maybe I should use a F5 series some day.
-- Regards, Joerg http://www.analogconsultants.com/
modulation.
be efficient?
-- Regards, Joerg http://www.analogconsultants.com/
network to gate.
Sure, but that's quite a lot of parts. I was planning on doing it with a single device plus optocoupler.
The MCP4011 series is listed at 15uA when operated at 2.7V. I could live with that :-)
-- Regards, Joerg http://www.analogconsultants.com/
estate.
That was just one example. There are many more, for example RF mixers that can go down to zero even though the datasheet often don't mention it. Typically well under a Dollar. AD makes good multipliers but that's more for precision scientific instruments where cost doesn't really matter. I don't need any precision here.
-- Regards, Joerg http://www.analogconsultants.com/
I gave one, see "b". You can get digital potmeters that are more accurate than 20% and cost more. But it's not isolated. No problem to communicate with one via optocouplers but the whole purpose of this post was to see if there's a more simple one-chip solution. Like the optocouplers that contain a 2nd diode so you can servo out the transfer function tolerance (but that's not resistive).
Then why did you answer?
-- Regards, Joerg http://www.analogconsultants.com/
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You do need some - you did mention 5% linearity. And multipliers are specified in a way that smears out the non-linearity over the whole of the range, which you can rarely completely exploit.
-- Bill Sloman, Nijmegen
I usually think "fast" and "accurate". You'd need a pantload of fancy parts to make something as linear and low-capacitance as an 0603 metal film. Of course for low performance jobs, something crappy like a
16-bit DAC may be enough. ;)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 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
[snip]
Ummmmmh! Larkin will claim that means you're an old hen and can't really design :-)
[snip] ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| 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.
modulation.
I just got the first boards back a few weeks ago, so haven't, yet. ;-) However, efficient should help. An extruded aluminum case should help, too (the final product will be in a casting).
As I said, it's cheating but it's really four phases, each at 500kHz. It's an advanced development project. One of the groundrules is that switching regulators must be above 2MHz (AM band). This cheating was the only way I found to get there. On another project, I have a couple of other smaller
2-phase buck regulators (2-phase, to get the power/efficiency up where its needed).
network to gate.
We don't always get our wishes.
Isn't the tolerance of the 4011 an issue?
modulation.
has
;-)
If you run them at 500kHz that's a bog-standard switcher range. That's not a 2MHz switcher. You won't be above the AM band with that unless you have a super-precise balancing system in there.
-- Regards, Joerg http://www.analogconsultants.com/
Cost
network to gate.
But I want my wishes granted!
:-)
It's exactly borderline but was only an example. I am pretty sure I can find one that is less than 20%. If not we'll have to do an auto-cal on start-up and the SW guys will throw their coffee mugs at me.
-- Regards, Joerg http://www.analogconsultants.com/
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