analog devices adau1592

[geekysuavo]

i'm pretty new to class-d, so i'm more familiar with tube designs. in that spirit, the analog devices series of integrated class-d amplifiers has caught my attention. i've designed a board based on figures 44, 45, and 49 in the device datasheet:
http://files.geekysuavo.org/classd/adau1592.pdf

my board design is available in open-source PCB format, Gerber format, and PNG format at http://files.geekysuavo.org/classd/ . the bom.html file lists the specific digikey part numbers of the components i chose.

if anybody is interested, it's up for grabs. more than anything, i'd love scrutiny of the design, as i'm still new to this amplifier topology.

thanks,
~ brad.

[dtproff]

Didi you get it powered up?

How did it perform. I'm curious

Tony

[geekysuavo]

actually, i haven't had the guts to order the pcb, considering i've never worked with surface-mount components before, and i have no idea whether or not the design is functional. sorry to disappoint.

~ brad.

[twest820]

I'm curious if anyone's aware of a class D chip with fidelity comparable to the ADAU1592 but available in a more DIY friendly package. I'm looking for class D solutions with peak outputs in the 1W to 10W range with performance equivalent or superior to the LM3886or LME49600. The ADAU1592 is the only chip I can find which meets these criteria. But its TQFP version is discontinued (and would be a hassle to solder) and the LFCSP is hard enough to work with its easier to put heatsinks on a class B part.

Failing that, are there any soldering services which would be able to stick a ADAU1592 at reasonable cost?

[vincent s]

I got this IC demo board.It performs well,sounds cleanly,but not powerful.

[theAnonymous1]

Originally Posted by twest820

I'm curious if anyone's aware of a class D chip with fidelity comparable to the ADAU1592 but available in a more DIY friendly package.

When you say "fidelity comparable to the ADAU1592", is this something you have actually heard, or are you just going by the numbers?

Do you think you could tell the difference in a blind test between 0.005% THD+N and 0.03% THD+N?

If not, the new TAS5615 or TAS5630 could be the answer. They have 15dB greater PSRR than the ADAU1592 (80dB vs 65dB), which to me is more important than the difference in THD. They have plenty of power to boot, which would address vincent's comment above.

[twest820]

Originally Posted by theAnonymous1

Do you think you could tell the difference in a blind test between 0.005% THD+N and 0.03% THD+N?

No, but I would like total distortion (and certain other artifacts) to be 50dB down for the overall system at output powers in the range of 100uW to 1mW. So reasonable confidence a chipamp would be around or below 0.1% THD+N at 1mW is desirable to allow some headroom for IMD and such. I appreciate the suggestion, but parts such as the TAS5615 and TAS5630 unfortunately aren't a good fit for this requirement (there's a reason I mentioned the LME49600 and peak outputs of 1W ). In fairness, the ADAU1592 is not speced that low either. But from its datasheet 0.1% into 8 ohms at 1mW doesn't seem an unreasonable expectation.

Since the THD+N scaling of class D amplifiers at low power isn't as good as class B I'd actually prefer a less powerful part than the ADAU1592, but lower wattage parts all seem to target the low-fi market of 1 to 10% THD+N. Whereas I'm trying to see just how much heat I can shave off the thermals of a low power hi-fi solution.

[Neil Davis]

Originally Posted by twest820

I'm curious if anyone's aware of a class D chip with fidelity comparable to the ADAU1592 but available in a more DIY friendly package.

The ADAU1592 isn't that hard to solder. Most of the pins are doubled or tripled, and the single pins really aren't that hard to solder. Just use lots of solder and then wick off the excess.

It's a very nice little amp. Dead quiet and low distortion.

active_xover_brd.jpg

[twest820]

Yeah, not too bad if you have TQFP old stock as used on the board above. If you don't, you're stuck with an LCSFP as the TQFP's discontinued. That's rather harder.

[Neil Davis]

Originally Posted by twest820

Yeah, not too bad if you have TQFP old stock as used on the board above. If you don't, you're stuck with an LCSFP as the TQFP's discontinued. That's rather harder.

The two ADAU1592 chips are LFCSP_VQ--they are on the right side of the board. I repeat: not that hard! All I have is a 30-year old Weller iron with a fine tip.

The stuff on the left side is an active crossover with TSSOP packages.


Look ma, no legs...
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