Texas Instruments TAS5261

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#302
-_nando-_ said:
I'm anxious to hear the feedback of the amplifiers ! 😉
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The amps don't have feedback so you won't be hearing anything due to that 😉 We will hopefully hear from the people who build these up though!

Some already know, but for those who don't: all the parts for the kits have arrived today (except for the inductors and wire which are on their way from CWS). I just took inventory and everything is accounted for.

Now it is time for me to head down to the laboratory, fire up the soldering iron, and start building up a board to test.

I test fit all the non surface mount components on the board and it looks pretty menacing with the large supply caps and inductors sprouting from the one side of the board :devilr:
 
#303
Well, the first snag has been hit.

Instead of the 0805 453ohm resistors (R31) I ordered I was sent some kind of cap in an 0603 package... Unfortunately they were labeled with the proper part number and I opened them up without looking... so it looks like I'll have to place another order. I'll call and ask to see if they can do anything but I'll probably have to place another order. The upside is I have to order at least $25 to avoid the handling charge and there's always $25 of parts I could use 😉
 
#304
I got one board fully built up except for the inductors. I managed to find some 1kohm 0805 resistors from another project, so I just soldered two of them in parallel to get 500ohms. That sets the 3.3V supply closer to 3.5V but is fine for testing.

I found a 15VDC wallwart supply, connected it to the 15V input, and tested the TPA2001D1 circuit. It works very nicely with an iPod as the test source! I had to change R23 and R24 from 10kohm to 0ohm because the 10kohm resistors and the input capacitance of the TAS5261 combined to form a low pass filter that created a sawtooth wave at the inputs of the TAS5261. Changing the values to 0ohm allows the square waves to pass through unattenuated. The square wave produced by the TPA2001D1 is nice and clean on my scope. It should be considering there are 3 levels of filtering for this chip's power supplies.

Tomorrow I will wind some inductors on the MPP cores, solder them on to the board, and see what happens when I give the TAS5261 some 24V rails.
 

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#305
I'd like to point out that the board is intended to be mounted with the chip facing upwards so that a heatsink can be placed on top of it. If you choose to mount the chip directly to a metal case you may cut the long standoffs to shorter lengths and place them at the four corners for better stability. For testing they will just sit on my desk/bench with a heatsink rubber-banded/zip-tied to the chip.

Stay tuned for more tomorrow.
 

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#307
" ... quote: Originally posted by -_nando-_ I'm anxious to hear the feedback of the amplifiers ! ..."

" ... The amps don't have feedback so you won't be hearing anything due to that We will hopefully hear from the people who build these up though! ..."

I believe he is asking about user "feedback" from those of us who actually try to impliment the device = real world reports of success, failure, pecularities, etc ... Not the electronic feedback of the device itself ... :cannotbe:
 
#308
" ... The upside is I have to order at least $25 to avoid the handling charge and there's always $25 of parts I could use ..."

See if they have any of that wire I sent in my care package = ~~#12 AWG silver clad or solid silver, very fine stranded with teflon coating .... my local source has run out and I need more and will of course pay for more ...
 
#310
" ... If you choose to mount the chip directly to a metal case you may cut the long standoffs to shorter lengths and place them at the four corners for better stability. ..."

Advise from afar:

1) For those of us concerned about such things: there is the possibility of long term galvanic activity when fastening to a steel chassis (and some other types of metal). I advise using the stand offs of the type found in electronic surplus houses ( as Brian has indicated he is obtaining) and an aluminum chassis = no galvanic activity questions.

2) The actual length of the stand offs should be almost exactly equal to or very slightly greater than the gap between the circuit board and the metal plate of the chassis ... If the stand offs are too short they can distort the circuit board upon tightening the mounts = possible board breakage or reliability problems = especially critical in mobile applications. (I intend to use plastic / nylon mounting screws on my mounted board so that they can not be tightened too tightly ...)

:smash:
 
#313
FastEddy said:
I believe he is asking about user "feedback" from those of us who actually try to impliment the device = real world reports of success, failure, pecularities, etc ... Not the electronic feedback of the device itself ... :cannotbe:
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I know Ed, I was just trying to make a joke. I guess my attempts at humor are a little dry at times 🙂

FastEddy said:
See if they have any of that wire I sent in my care package = ~~#12 AWG silver clad or solid silver, very fine stranded with teflon coating .... my local source has run out and I need more and will of course pay for more ...
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I'll have a look through the Digi-Key catalog to see what I can find. If you find a part number please let me know.

FastEddy said:
Via the analog output ?? ... or the USB ??
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Analog output. I don't have the ability to use the USB output.

FastEddy said:
Advise from afar:

1) For those of us concerned about such things: there is the possibility of long term galvanic activity when fastening to a steel chassis (and some other types of metal). I advise using the stand offs of the type found in electronic surplus houses ( as Brian has indicated he is obtaining) and an aluminum chassis = no galvanic activity questions.

2) The actual length of the stand offs should be almost exactly equal to or very slightly greater than the gap between the circuit board and the metal plate of the chassis ... If the stand offs are too short they can distort the circuit board upon tightening the mounts = possible board breakage or reliability problems = especially critical in mobile applications. (I intend to use plastic / nylon mounting screws on my mounted board so that they can not be tightened too tightly ...)
Click to expand...

That is excellent advice. The standoffs included with the parts kits are aluminum with an iridite finish (whatever that is); 4-40 thread size (6 screws will be included as well). Also, the pads that touch the standoffs are not electrically connected to the board in any way. One of the through hole pads next to the TAS5261 is connected to AGND, as it is recommended that the heat sink connected to the TAS5261 heat slug be grounded.
 
#314
aaronlow said:
Could you post your eagle PCB files for this design?
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I posted the schematic and parts list because those are relatively easy to come up with (my implementation is a little different from what TI recommends though), and most of it is information that is freely available from TI anyway. The board layout, however, is not trivial and takes a good deal of effort to produce. That's the main reason I won't be posting the layout files. It's not that I don't trust you, it's just that anyone can easily rip off the design if they have the layout files.
 
#316
Instead of the layout could you post the TAS5261 library file. That is all I really need. I also called TI and requested the recommended PCB footprint for this part. If TI recommends dimensions other than the used library, I will post the corrections to the DKD (R-PDSO-G36) footprint.

Thanks
 
#317
" ... I know Ed, I was just trying to make a joke. I guess my attempts at humor are a little dry at times ..."

Speaking of dry: where do we get that cute little smiley face that drinks beer ?? Can we add it to the list at the left?

" ... ~~#12 AWG silver clad or solid silver, very fine stranded with teflon coating .... my local source has run out and I need more and will of course pay for more ..." " ... I'll have a look through the Digi-Key catalog to see what I can find. If you find a part number please let me know. ..."

I got it off of a spool at our local parts surplus house = no more available = no specs other than above = :bawling:

" ... I don't have the ability to use the USB output. ..." Meaning a) that you have a very old computer? and/or b) that the circuit is not capable of transmitting digita USB audio to the amp input ...?? I should have known this as the USB is almost certainly command and control only ... Yes?

" ... standoffs included with the parts kits are aluminum with an iridite finish (whatever that is) ..." The finish is a residual of the cleaning & anodizing process = usually too hard to remove so they call it a "feature" rather than a liability = No problem-o, SOP for the electronics industry.

" ... the pads that touch the standoffs are not electrically connected to the board in any way ..." Good show!!

" ... One of the through hole pads next to the TAS5261 is connected to AGND, as it is recommended that the heat sink connected to the TAS5261 heat slug be grounded. ..."

Also a good thing ... although maybe not a necessity. <b>Does this mean that TI recommends connection of the heat sink (in this case, the case) be electrically connected to AGND ??</b>

:smash:
 
#318
aaronlow said:
Instead of the layout could you post the TAS5261 library file.
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Yes, I can post the footprint I used when I get home. It's a modified version of the PSOP-36 package that is actually somewhere in the eagle libraries. I found it once but can't remember which directory it was in.

FastEddy said:
" ... I don't have the ability to use the USB output. ..." Meaning a) that you have a very old computer? and/or b) that the circuit is not capable of transmitting digita USB audio to the amp input ...?? I should have known this as the USB is almost certainly command and control only ... Yes?
Click to expand...

The TPA2001D1 will only accept an analog input. The TAS5261 accepts PWM input control signals, not a digital bitstream. You'd need to convert the PCM bitstream to a PWM signal if you wanted to bypass the TPA2001D1.

... of course my computer has USB ports :clown:

FastEddy said:
Also a good thing ... although maybe not a necessity. Does this mean that IT recommends connection of the heat sink (in this case, the case) be electrically connected to AGND ??
Click to expand...

A while back in the thread kims or mp8 said the heat slug should be grounded. The heat slug is not connected to anything internally so it could be left floating if that's what you want.
 
#319
It's a modified version of the PSOP-36 package that is actually somewhere in the eagle libraries. I found it once but can't remember which directory it was in.
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Did a quick search and this is what I found. The L6207PSO36 from ST-Microelectronics. Don't know whether this is the one you mean.

Regards
 

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