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-   -   TPA3118D2 (http://www.diyaudio.com/forums/class-d/219730-tpa3118d2.html)

fakeout 14th September 2012 09:48 PM

TPA3118D2
 
Has anyone ordered the evaluation model to hear what it sounds like?

TPA3118D2EVM
TPA3118D2 Evaluation Module - TPA3118D2EVM - TI Tool Folder

The video on the TI web site makes it sound impressive. (Video is at the bottom of the page.) http://www.ti.com/product/tpa3118d2

xrk971 15th February 2013 12:53 AM

I just ordered the TPA chip and all essential components in the bill of materials in the eval board spec sheet. I upgraded the input caps to film and boosted the main electrolytics. I have never assembled a SMD circuit before so this could be a challenge. I was going to do it dead bug style using the clever pva glue technique suggested on a recent thread. The eval board was just too pricey at $150 whereas everything in parts cost $15. The specifications on paper are very impressive: 25 honest watts into 8 ohms at 0.1% THD with 24 volt power supply and 90% efficiency. I will have to check out video - have not seen it yet. I have heard rumors that this chip is very 'tubelike' in sound.

wushuliu 15th February 2013 08:51 PM

Quote:

Originally Posted by xrk971 (Post 3370316)
I just ordered the TPA chip and all essential components in the bill of materials in the eval board spec sheet. I upgraded the input caps to film and boosted the main electrolytics. I have never assembled a SMD circuit before so this could be a challenge. I was going to do it dead bug style using the clever pva glue technique suggested on a recent thread. The eval board was just too pricey at $150 whereas everything in parts cost $15. The specifications on paper are very impressive: 25 honest watts into 8 ohms at 0.1% THD with 24 volt power supply and 90% efficiency. I will have to check out video - have not seen it yet. I have heard rumors that this chip is very 'tubelike' in sound.

How do you solder a chip like that by hand? It is so freakin' small with so many pins!

xrk971 15th February 2013 09:37 PM

Wushu,
I know it isn't gonna be easy! My thinking is to stabilize it by gluing it to a printout of the circuit (the eval board schematic - not pcb layout as that is too tight) with PVA white glue as suggested by Seanvn in this thread: http://www.diyaudio.com/forums/const...struction.html. But instead of removing the glue by soaking in water, I am going to leave it on the paper which will be affixed to a foam core board. You need steady hands and work slowly - like surgery. I am in no rush and will work sections at a time. In thinking about what I am getting myself into, it is looking harder and harder and I may end up failing miserably :) But hey, it can't be any worse than watchmaking! In hindsight, I should have subsituted thru-hole components where possible to get things larger but I was lazy and just bought the parts on the bill of materials verbatim by doing keyword searches for part numbers in Digikey. To manually figure out what the equivalent through hole component would be would have taken some time and I may have ended up making a mistake and having just as much of a problem.
Anyhow, we will see how it goes. If it works I will have a killer budget amp. :D

OK, after some searching, the breakout board for HTSSOP is $10. I will probably get this.
http://www.proto-advantage.com/store...cts_id=3100103
http://www.proto-advantage.com/store.../IPC0093_0.JPG

fakeout 17th February 2013 09:27 AM

Wow, someone responded. Well, I can't wait to hear how it works out. If you like the sound, it would be nice to see instructions on how to put it together. (Or, even a Youtube video.)

Boscoe 17th February 2013 11:47 AM

Xrk you should of got the top cooled package as your meant to solder the bottom pad to the pcb and you can only so this with solder paste. SMD is easy just solder opposing corner pins of the chip to stabilise it then solder the rest of the pins. I can do one in a minute or so.

xrk971 17th February 2013 12:13 PM

My components all arrived! I opened the box and looked at the SMD parts I ordered. I realize how naive I am because the parts from TI's bill of materials are absolutely the smallest of the small SMD part sizes. You need a microscope to even see it.;) I will have to order a magnifying set of goggles like what watchmakers use and solder paste and liquid flux - after watching some youtube videos of how to assemble and solder SMD components. What this means is that a very capable moderately powered amp can be made on a circuit small as a credit card. Does anyone have a suggested vendor they use for making custom pcb's. I have looked online and there are so many. I have enough parts to try this using my crazy paper based approach first. It will be interesting but I foresee a period of eyestrain coming up! :D

rsavas 19th February 2013 06:53 PM

With a fine tippped iron, small OD solder, a steady hand, you should be able to do this without resorting to needing solder paste etc. I use a 10x jewelers loom magnifier.
Soldering the thermal pad is another story, if a large via is underneath the part you can flow solder through the via to the other side.

xrk971 19th February 2013 07:49 PM

Quote:

Originally Posted by rsavas (Post 3376862)
With a fine tippped iron, small OD solder, a steady hand, you should be able to do this without resorting to needing solder paste etc. I use a 10x jewelers loom magnifier.
Soldering the thermal pad is another story, if a large via is underneath the part you can flow solder through the via to the other side.

I just ordered the jeweler's loupe (actually binocular magnifier goggles). I have a pretty small tip iron and fairly small size solder. I plan to deal with the thermal power pad by flipping the chip on its back like a dead bug with legs in the air (truly dead bug assembly! ;) ). I will then either solder or clamp a heat sink (copper rod with fins) onto the now exposed thermal pad. There is a variant of the chip with thermal pad located on top (the 50W TPA3116 comes this way standard).

rsavas 19th February 2013 08:15 PM

And you want to do what?, try to solder onto the leads hanging in the air = crazy!!
Drill a hole through the center of the exposed pad on the PCB, enough to get the soldering iron tip to heat up the exposed pad, on the IC & the PCB, next, solder the components leads as usual, right side up, then finally solder the exposed thermal pad afterwards.


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