Cheap TPA3118D2 boards, modding them and everything that comes with it

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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.
 
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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!
 
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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/construction-tips/224124-paper-glue-smd-circuit-construction.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/product_info.php?products_id=3100103
IPC0093_0.JPG
 
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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.
 
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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
 
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.
 
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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).
 
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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Is it crazy? I was going to skip the breakout board - so no PCB whatsoever - just gluing everything to a board to stabilize before point-to-point soldering. The upside chip actually provides good access to the pins for soldering each one with a fine wire like how dies are attached inside an IC. I have a printed PCB on the way, but wanted to try this crazy idea of a dead bug TPA amp.
 
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.

This is what I do if possible, drill a 2-3mm dia hole where the pad should be, affix the chip as normal, flip the board then solder the exposed pad. To do this I flow in a lot of solder till the whole is filled to the reverse copper plane with a plug of solder. It works fine and even with LEDs if you're very careful to limit exposure time with a low temp iron.

If a part is too small I drill a 1.5mm hole and place a 1.5mm copper rod through the hole, sanded flat beneath the chip and soldered to the backside copper with tin solder. I then solder the rest of the chip in place with lead based solder paste + cheapo small electric oven/hot air gun (the oven works better).


The tpa is big enough for the first method to work well.
 
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5th Element,
I thought of doing the very thing you describe. When I get a PCB I will use the TPA3116 which has the thermal pad on top for a heatsink. For grins, I am going to do the dead bug manual wire bonding approach with the SMD components glued to a foam core board with PVA glue. I think the biggest thing I have to watch for is bridging the pins. They are spaced 0.6 mm - pretty small but we will see... :) Slow and steady, I think the magnifying googles will help. I fear it will not work but the chips are cheap to try and I will have a "foam core amp" to go with my foam core speakers! :D
 
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Foam Core Amplifier begins

Ok, so I took all your suggestions and agree that this is crazy but I am doing it anyway. I laid out the smd components and glued them in place with acrylic clearcoat (smd) and hot melt for larger thru hole stuff and terminals. There is a layer of foil underneath paper for ground plane. The whole thing is on a 4 x 6 inch foam core board. Note the dead bug upside down TPA3118 chip. This was actually pretty fun to do. The hard part of soldering is next. Slow and easy... :)
 

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My magnifying goggles came today - wow what a difference they make. I can actually see the text on the resistors (0603 size) which are the size of a flea. The binocular goggles have a 3x flip down lens on top of the 1.5 x main lens and a 9x swing out loupe all with LED illumination. Very handy. As soon as I have some time I will start the manual wire bonding with a soldering iron and flux core solder. I am told liquid flux in a hypo syringe is key for this sort of stuff but that would results another order.
 
It will be easier to solder the chip on the adaptor then solder the rest of the part around it. Soldering wires directly on those 0.5mm pitch pins is not gonna be easy, even if you have the proper PCB for it without the right tools and experiences/skills can be a challenge.

Why not make PCB for it? its a useful skill to learn than doing it that way LOL.

Well good luck, let us know how it goes.
 
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I may have to go with an adapter the next time if this fails. I think the hardest part will be soldering wires to the pins, which are actually 0.6 mm pitch according to drawings. I plan to use thin wire wrap style wires for connections to pins. Making a pcb will definitely be something I want to do at some point if the bug bites me, kind of like making speakers. I don't want to do the actual acid etch and screen printing, drilling myself. Using a pcb fab house is only option and they are charging $70 per run of 3 boards. Do you guys have suggestions for a fabricator? They all have software you can download and start designing boards with. I am worried about making a mistake and you are stuck with bad boards.
 
Hey X,

Show us a photo of those glasses! And if possible a link to where you got them on Amazon.

There's bunches of them out there, and I'd like to get a pair that's worth the money.

Happy soldering!

I was just looking at that "breakout board" you mentioned earlier. That's interesting and probably worth the $10.

Mark