TPA3120D2: Competition for your T-Amp?

[theAnonymous1]

Has anyone thought about making a board for this new TI chip? It looks fairly simple to implement. It would make a nice "mono block" style amp in BTL configuration. Perhaps give your low powered T-amp a run for the money?

I would give it a go myself, but I would like to see what someone who actually knows what their doing can come up with; i.e. BWRX (hint hint ).

http://focus.ti.com/docs/prod/folder...tpa3120d2.html

[BWRX]

There are some things I don't particularly like about this chip: the price, the package isn't the most DIY friendly because of the thermal pad on the underside, the osciallation frequency is only 250kHz and cannot be changed, the gain setting resistors are not accessible, and the input stage is very similar to what the Tripath chips use... but the circuit is simple enough and I've got some samples on the way so I can't let them go to waste

We will definitely want to use this as a mono BTL amp to get the most out of the chip and the configuration. This will be open source and I'll make the schematic and layout files available so everyone can tinker and play around with them. And since it is open source any comments, suggestions, etc. are welcome. If there is enough interest I could do a group buy for the PCBs, but I do not have the time to do one for parts as well.

The TPA3120D2 is available at Digikey with the following qty/price breakdown:
QTY/UNIT PRICE
1/6.40
25/5.12
100/4.32

[theAnonymous1]

Originally posted by BWRX
There are some things I don't particularly like about this chip: the price, the package isn't the most DIY friendly because of the thermal pad on the underside, the osciallation frequency is only 250kHz and cannot be changed, the gain setting resistors are not accessible, and the input stage is very similar to what the Tripath chips use... but the circuit is simple enough and I've got some samples on the way so I can't let them go to waste

We will definitely want to use this as a mono BTL amp to get the most out of the chip and the configuration. This will be open source and I'll make the schematic and layout files available so everyone can tinker and play around with them. And since it is open source any comments, suggestions, etc. are welcome. If there is enough interest I could do a group buy for the PCBs, but I do not have the time to do one for parts as well.

The TPA3120D2 is available at Digikey with the following qty/price breakdown:
QTY/UNIT PRICE
1/6.40
25/5.12
100/4.32

Did I ever mention your my hero Brian?

I'm staring at one of these IC's right now, and while I think I can handle soldering the pins, I'm not so sure I can do the thermal pad with the (lack of)equipment I have. What is the best way for a DIYer to solder a thermal pad like this? IR, hot air, toaster oven? I was thinking as a last resort for myself I could always just use an extremely small amount of thermal epoxy on the pad and then solder the pins the old fashioned way.

[BWRX]

Originally posted by theAnonymous1
What is the best way for a DIYer to solder a thermal pad like this?

The best way is probably using solder paste and some sort of oven. The next best way is a big old soldering iron. I don't have the proper tools at home either, but I may be able to coerce some people at work to let me use the reflow oven. If that doesn't work the thermal epoxy may be the next best solution.

[BWRX]

Since I'm tired of winding my own inductors I'm looking into the surface mount types offered by Coilcraft and Pulse (if you know any other good manufacturers let me know). Because of the low switching frequency and bridged output we will want them to be around 20uH with a saturation current of at least 5A, preferably twice that. That basically narrows down the type to a drum core or laydown toroidal.

The MSS1278-223ML (22uH 6.2A) from Coilcraft is cheap, magnetically shielded, and has a reasonably small footprint. Pulse has some inductors worth considering too.

[Pano]

I thought the SMD Coilcraft on the amp you sent me were nice, Brian.

That would be my choice.

[BWRX]

The SER1360 inductors from Coilcraft are nice but they only go up to 10uH. That's fine for an amp with a higher switching frequency like the D10.1 (600-700kHz) but the TPA3120D2 has a fixed switching frequency of 250kHz.

[theAnonymous1]

How about Coiltronics HC9-220-R 22uH 6.3A.

http://www.cooperbussmann.com/pdf/26...4b52387e1f.pdf

Their available from Digikey for $2 each in quantities of 10.

[BWRX]

Those look very nice as well. Good find. It's also the only one Digikey has in stock with those specs

I browsed through the Coilcraft surface mount power inductor selection again and noticed the SER2800 series. They look like the SER1360s on steroids. This is more like what I was looking for except they only come in an unshielded package, are unfortunately quite a bit larger (but not quite prohibitively so), and cost around $3.50-4 each.

[Pano]

Originally posted by theAnonymous1

http://www.cooperbussmann.com/pdf/26...4b52387e1f.pdf

I would definitely NOT use those coils from Cooper Bussman. If you look closely you will see that they are located in Boca Raton, Florida.
Nothing wrong with that, I went to high school there.

But look at the address.
They are on "Broken Sound" Parkway! No way I want those in my amp.