TAS5015 is now NRND, comments/possible replacement wanted - diyAudio
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Old 13th December 2004, 03:47 AM   #1
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Default TAS5015 is now NRND, comments/possible replacement wanted

Hi,

Just discovered the awesome diyAudio forums, glad that something like this exists

Now, there's the question I have:

As I recently noticed, TI changed status of TAS5015 to NRND (not recommended for new designs) so that means it will be discontinued soon.

So I wonder, what would make a good replacement for high quality class D amp (maybe TAS5076 or recently introduced TAS5518?), also I would be glad if someone has any idea about possiblity of bypassing current TI modulators' PLLs (since TAS5015 was the only device with external PLL) and using external PLL or oscillator to reduce clock jitter?

Or maybe current TI offerings are no match for the 5015 and I must hurry to by a pack while it's available from distributors?



(some background) I was planning to make a TAS5015-based amp to use it as a part of "HD-box" consisting of a embedded processor (plus maybe a DSP), HD interface, 250Gb HDD and probably ethernet interface - which I think would be a very nice device to have - pretty useful since it could use data from many sources (CD, DVD-A, DAT) being independent of the exact transports and could be also used inside the car to make awesome car audio system cheap

Regards,
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Old 13th December 2004, 08:54 AM   #2
kims is offline kims  Denmark
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Default TAS5015 NRND, change to TAS5518

Hi

The TAS5015 is change to NRND due to the relatively low demand for this device.

The TAS5076 is the 6-channel version of the TAS5015 using the same modulator core, but with 6channels and integrated volume control. Both the TAS5015 and the TAS5076 uses BD-mode modulation.
TAS5015 can acheive around 110dB DYR depending a lot on the PCB design, usign a external oscillator in master mode.
TAS5076 can not use an externel PLL or oscillator, it is always using the internal PLL. With the right set-up the TAS5076 has around 107-8dB DYR.

The TAS5508 and TAS5518 is the new modulators from TI, using an updated PWM core, and new PLL structures.
TAS5508 acheives 102dB DYR, and the TAS5518 acheives 110-112dB DYR on all 8channels.

Both TAS5508 and TAS5518 have more features than the TAS50xx series, like BAS, Treble, DRC, Loudness, input/output mixing etc.
The 7-biquads in each channel is an easy way to do cross-over for an active speaker system.

The TAS5508 and TAS5518 is using fully symetrical AD-mode modulation with a 5-order noise shaper, so the noise floor is flat in the audio band.

Personally I think that the sound quality of the TAS5518 is better than the TAS5015, and it is easier to design with due to the use of AD-mode modulation.

Rgds,

Kim
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Old 13th December 2004, 11:17 AM   #3
JohnW is offline JohnW  Hong Kong
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By all accounts the TI5015 is a very good sounding modulator – with the best 19 & 20KHz IMD I’ve measured to date – better then -115dB (18 & 21 KHz), this is also better then any linear amplifier I’ve measured.

Dynamic range -115.9dB non Awtd, however the in band noise floor shows the effects of the “Poles & Zeros” of the noise shaper – see 1W FFT plot below.

You could also look at the Renesas M65818AFP; the great advantage of this device is its inbuilt ASRC. With the earlier device the M65817AFP I achieved a dynamic range just shy of -120dB. However its 19 & 20 KHz performance was not as good as the TI at about -95dB. It also operates the output stage at around 768 KHz – better from an EMC perspective, but places greater demands on the output stage

Sounds like and interesting project – good luck,

John
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Old 13th December 2004, 09:49 PM   #4
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kims, thanks for the information, furthermore, it seems like that's good news for me.

I think TAS5518 would be a safe bet for my design (it would also simplify it since TAS5518 is much more integrated).

Also, could you elaborate why AD-mode design is easier than BD-mode? I suppose that's because AD-mode is less sensitive to unmatched delays beetween high and low side MOSFET drivers in half-bridges?

Regards,
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Old 13th December 2004, 09:49 PM   #5
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JohnW,

TAS5015 just gotta be very good sounding since even Tact Millenium now uses it

How do you think it compares in terms of resulting sound quality to two other TI modulators that may be used in construction of good amp, TAS5076 and TAS5518 (And especially the latter since it uses different modulation type)?

Thanks for the M65818AFP reference - looked at it, seems nice, but I haven't found a single distributor stocking them (looked on findchips, partminer and my country local search engines - not a single hit). Do you have any ideas how one could purchase it in a small quantities?

Regards,
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Old 13th December 2004, 09:49 PM   #6
gooftar is offline gooftar  France
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Default My Tas5518 design

Hi,


I have made my PCB for the tas5518, it has an spdif receiver (DIR1703) for stereo source and a possible connection to a DSP device via I2S. The tas5518 modulator is connected to 8 tas5121 output stages.

The control part is done with an MSP430 also from texas (essentially driving an lcd and receiving infrared commands to control the modulator)

A second board (Front panel board) feature the LCD and the IR receiver.

Please see photos and schematics (in Eagle format) and also Gerber&excellon files on :
laurent.legoffic.free.fr/TDAA8/

Any comment or remarks apreciated !
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Old 14th December 2004, 08:16 AM   #7
JohnW is offline JohnW  Hong Kong
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With BD modulation, it’s the matching between the 2 sides of the HBridge that’s important. The error between the 2 sides appears as a form of Phase modulation – elevating the noise floor.

Ah good question, I bought a Sony DAV-S400 just to Evaluate its modulators (the M65817AFP), Renesas Fab the Sony modulators, that’s the S-Bit connection. Yes a brand new Sony – pull apart for a modulator!

Wish I could be of more help,

Gooftar,

I don't have a copy of Eagle, so I cannot comment on your PCB files - but I understand that the TI DIR1703 is no longer available.

John
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Old 14th December 2004, 06:03 PM   #8
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gooftar,

Nice board. How does it sound?
(Maybe you have some THD+N or dyn. range measurements/estimations, that also would be nice)

It seems you do not use variable PSU for volume control, am I right?

Regards,
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Old 14th December 2004, 06:03 PM   #9
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JohnW,

Do you have some pointers about where I can read more on AD vs. BD modulation subject? Tried searching this forum, but hardly found anything useful.


About poor DAV-S400 - was it worth? I mean evaluation gave some good results?

Btw, Gooftar's site has schematics and pcb image in some common picture format too, so Eagle isn't needed really.


Regards,
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Old 21st April 2006, 04:29 AM   #10
jwton is offline jwton  United States
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Question What version of Eagle

I was trying to open the files that gooftar posted above, but I receive and error message that the files are corrupt or created with an illegal version. I have tried ver 4.13 and 4.17 and can not open the files.
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