Wanting to build a compressor for my bass and staring with the RMS detect. The RMS ICs from Analog Devices at Digikey cost $30 to $200 per IC!!!
PMIC - RMS to DC Converters | Integrated Circuits (ICs) | DigiKey
Even though the AD site has them all for under $20. WTF?
Selection Table for RMS to DC Converters | Parametric Search | Analog Devices
Am I missing something?
And it also looks like through hole ICs are dissapearing, sad for DIY, are there adapters for surface mount ICs so you can use them in through hole designs?
PMIC - RMS to DC Converters | Integrated Circuits (ICs) | DigiKey
Even though the AD site has them all for under $20. WTF?
Selection Table for RMS to DC Converters | Parametric Search | Analog Devices
Am I missing something?
And it also looks like through hole ICs are dissapearing, sad for DIY, are there adapters for surface mount ICs so you can use them in through hole designs?
On Digikey, they have the variations. ANy with an S in the suffix have extended temp range. Instead of 0 to 70C, they S ones go from -55 to +125C.
The J and K types are two different accuracy grades.
Those are just for starters.
As to the selector guide, note that your part is only the last one on the list. The other ones are different types of IC. They list yours as $10. But look up top, that $10 is the price when you are buying them by the THOUSANDS.
I suspect that was what you were missing.
Most of the selections on teh Digikey page were for throughhole rather than surface mount.
The J and K types are two different accuracy grades.
Those are just for starters.
As to the selector guide, note that your part is only the last one on the list. The other ones are different types of IC. They list yours as $10. But look up top, that $10 is the price when you are buying them by the THOUSANDS.
I suspect that was what you were missing.
Most of the selections on teh Digikey page were for throughhole rather than surface mount.
The facts that they are laser trimmed to a high degree of accuracy and that almost no-one uses them surely also increase the costs:
1. Fancy IC process with laser trimming capability required
2. Very expensive test equipment used to actually do the trimming
3. Expenses shared between a very limited number of customers
4. Probably the highest accuracy grades are selected out of a batch of ICs by again using expensive test equipment
5. Hermetic ceramic package rather than cheap plastic for the most expensive military/aerospace (extended temperature range) types
1. Fancy IC process with laser trimming capability required
2. Very expensive test equipment used to actually do the trimming
3. Expenses shared between a very limited number of customers
4. Probably the highest accuracy grades are selected out of a batch of ICs by again using expensive test equipment
5. Hermetic ceramic package rather than cheap plastic for the most expensive military/aerospace (extended temperature range) types
Aren't the lower ADI prices only in large quantities?
Digikey would be similar pricing in quantity, ask them if not listed.
The mfr will never undercut their distributors, that's shooting yourself in the foot.
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Not buying that eithier. This IC includes the RMS plus a much more involved circuit and the price is under $10, if it wernt surface mount I would buy it.
THAT Corporation 4305 Low-cost Analog Engine - Dynamics Processor IC
By the way, do you really need to detect the RMS value or is the average absolute value close enough? That you can detect with a few dirt-cheap diodes, op-amps and resistors. If true RMS is needed, you could make your own translinear RMS detecting circuit using transistor arrays, although that may well become more expensive than $30 and will certainly become less accurate than the AD parts.
The accuracy of the RMS detector is nowhere near that of the Analog Devices part, and I don't see any military/aerospace variant in the datasheet.
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Then you want the dBx/THAT chip, MADE for audio; not the instrumentation chips.
Music compression does not need 0.5% precision; 10% is 1dB which is don't-care for audio. 60dB range is not needed for music limiting.
You can get LTC1966 on a handy small PCB from Taobao for under $5 : https://detail.tmall.com/item.htm?spm=a230r.1.14.25.73985db7QxVIhz&id=601622821061&ns=1&abbucket=4
Just a guess but it may be used in military gear that requires spares. That is probably an old IC.
Neat thing about ADI is while they cost more, they keep chips in production for a long time. I
started using the AD811 video opamp in 1992. These are still in production. Another good thing
is their chips actually do what they claim to do. I will happily pay more for the better performance.
Some devices are selected for better performance with an A or B suffix. It's nice when you measure
an AD588 reference with a Fluke 4 1/2 digit meter and if you don't read 5.000V you adjust the
meter. Personally I would not have a problem buying a less expensive chip on eBay. Unlike opamps
that come in a wide variety but the same pinouts, I don't think there is much market for knockoff
RMS to DC converters.
Of course you could A-D and DSP.
G²
Neat thing about ADI is while they cost more, they keep chips in production for a long time. I
started using the AD811 video opamp in 1992. These are still in production. Another good thing
is their chips actually do what they claim to do. I will happily pay more for the better performance.
Some devices are selected for better performance with an A or B suffix. It's nice when you measure
an AD588 reference with a Fluke 4 1/2 digit meter and if you don't read 5.000V you adjust the
meter. Personally I would not have a problem buying a less expensive chip on eBay. Unlike opamps
that come in a wide variety but the same pinouts, I don't think there is much market for knockoff
RMS to DC converters.
Of course you could A-D and DSP.
G²
Hard to get tubes into a guitar pedal 
And hard to pay more for the ICs to DIY than a comercial product off the shelf.
Thanks for all the replys and a special thanks to Scott for the offer.
The best solution to this is to go surface mount, and get the Audio engine from THAT but Ive never tried to DIY with the tiny packages, is it possible? I cant be the only one hear with this question. Off to search this site.
And hard to pay more for the ICs to DIY than a comercial product off the shelf.
Thanks for all the replys and a special thanks to Scott for the offer.
The best solution to this is to go surface mount, and get the Audio engine from THAT but Ive never tried to DIY with the tiny packages, is it possible? I cant be the only one hear with this question. Off to search this site.
Found these adapters: 9163 Capital Advanced Technologies | Prototyping, Fabrication Products | DigiKey
Looks like the way to go. Shows what a good deal most ICs are when this little adapter board costs as much as a coplicated, pre trimmed, niche IC.
THAT Corporation 4315 Low-voltage Low-power Low-cost Analog Engine Dynamics Processor IC
$6 at mouser for 1.
Looks like the way to go. Shows what a good deal most ICs are when this little adapter board costs as much as a coplicated, pre trimmed, niche IC.
THAT Corporation 4315 Low-voltage Low-power Low-cost Analog Engine Dynamics Processor IC
$6 at mouser for 1.
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