"Proper" TDA3116 PCB

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gmarsh

gmarsh

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Joined 2004
rsavas said:
It just occurred to me, DFM review
I have no idea about your mfg plans, but if you ever decide that you want these pcb's sent out to a sub-contract mfg, for assembly, you might want to put on 3 imaging fiducials, for the pick and place machine registration/alignment.
These are usually put in 3 corners, of the pcb, on each side SM comps are mounted on. Clear of traces underneath.
The global fiducials can be put underneath TH comps, as they usually go on after reflow.
Another DFM rule was to use one or two fiducials, for each fine pitch sm comp, if pitch was < 50 mil. One in the middle or two on opposite corners of a qfp.
Not sure if they can image, using the via smack in the middle of the via array underneath the TPA. Have to ask the CMfg on that one.
You have 4 tooling holes (might not be the preferred hole size) for a stencil alignment, so you are good there.
You have a few TH comps, so the mfg would decide if they do a wave or hand back load , it really depends on the qty involved. There was also another option where they did a selective wave process rather than hand soldering which adds cost, even if it is done in Asia.
Click to expand...
The plan right now is hand assembly. If everyone wants my wiener and I can't keep up with demand, I'll do machine assembly at the local board house and update the PCB with fiducals etc. as required then - it'll have to be reordered on panels anyway.

This board is top side SMT only, so the TH can be done with full wave or selectively. The board house I work with has both machines, guess it's their call which one they use if I go that route. Other than changing 4 electrolytic caps there isn't really much through-hole I can get rid of - the film caps and inductors are TH only, and I don't trust the mechanical strength of surface mount terminal blocks.
 
R

rsavas

Member
Joined 2012
Interesting observations.
TPA32xx? What is the exact part number and on what board/design?
That is not my experience with the TPA3100D2.
I guess I could wire the TPA3118 pcb into my portable, remove the ATtiny and have the xmega do the control to see if it behaves any differently. I have a SE input similar to this TPA3118 design.
To note the differences, I had control over the signal source Z, also I could mute my MAX9729, thus signal sources while I do a switch in sources, but that has nothing to do with the TPA3100.

In my code
Code: 
Config Portc.6 = Output
Max9729_shdnx Alias Portc.6
Set Max9729_shdnx

Bunch of other device initialization then

Code: 
'----------------------------Initialize MAX9729---------------------------------
'Dim Max9729_reg0 As Byte                                    'B7=shutdown,B6,B5=mixer control,B4-B0=Volume
'Max9729_reg0 = &B1_00_11111                                 'Default: enabled, input channel 1, volume = Mute
'Dim Max9729_reg1 As Byte                                    'B7-B5=beep atten,B4=1,B3=Bass enable,B2-B0=Max gain
'Max9729_reg1 = &B000_1_0_011                                'Default: Beep (0), BassMax=Disabled, Gain=10dB                                                'Display the Volume at startup on Line 2
Volume = 0
Max9729_max_gain = &B100
Volume_count = 0                                            'used by encoder2

Display_volume

Volume_temp = Not Volume
Volume_temp = Volume_temp And &B0_00_11111
Max9729_reg0 = Max9729_reg0 And &B1_11_00000                'mask out volume bits 4-0 & pass bits 7-5
Max9729_reg0 = Max9729_reg0 Or Volume_temp                  'merge complemented volume setting with bits 7-5
'Max9729_reg1 = Max9729_reg1 And &B1111_1000
'Max9729_reg1 = Max9729_reg1 Or Max9729_max_gain
Max9729_set_volume
'Locate 2 , 17                                               'debug
'Lcd "Reg0_1=" ; Bin(max9729_reg0) ; " " ; Bin(max9729_reg1)
'------------------------------Initialize TPA3100-------------------------------
'check if external power being applied or if supply from one of the USB ports, to determine setup of TPA3100
If Ext_v_mon = 1 Then
  Set Tpa3100_sdx
  Reset Tpa3100_mute
  Reset Tpa3100_gain0
  Reset Tpa3100_gain1
  If Tpa3100_fault = 1 Then
    Reset Tpa3100_sdx                                       'disable if TPA3100 reports fault indicating output short condition
    Set Tpa3100_mute
  End If
Else
  Reset Tpa3100_sdx
  Set Tpa3100_mute
  Reset Tpa3100_gain0
  Reset Tpa3100_gain1
End If
Pretty simple, no pops what so ever.
It is handy to be able to mute the MAX9729, as you switch signal sources and that eliminates popping from the sources.

"gmarsh", sounds like you have been through the DFM review before, :) so happy soldering. Find a nice comfortable chair.
update the PCB with fiducals etc. as required then - it'll have to be reordered on panels anyway.
Click to expand...
One more NRE charge, not a biggie, same as if you send it out to another fab.
I think it took me two days to solder up the portable proto, enough to know, I am not a fan of hand soldering the DFN package.
 
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gmarsh

gmarsh

Member
Joined 2004
voltwide said:
Today I did some investigations on turn-on/turn-off plopping of TPA32xx. So I built a simple Attiny25 controller, flashed some power-up/power-down sequence into it and connected the ports to mute and SDZ.
On the other hand, I wanted to enforce plopping, so I connected one analog input via 100uF+10k to GND, the other left open. This gave considerable plopping, specially at power-down.
And the result is, the Attiny25controller did NOT suppress that anyway!
So, what went wrong? -
I will give some ideas
Whenever you hear any noise from the amp, there is a voltage differential between the two legs of the h-bridge. So, if voltages of both legs build up exactly the same during power up and power down the differential cancels and there will be no plopping at all. But if there is some plopping this is an indication of asymmetric behaviour of the h-bridge, i.e. some kind of mismatch between both half-bridges.
This became evident with the prototype of doctormord which I could check here. Plopping was at its max with the 10kOhm input pot in center position, but vanished in the end positions. The explanation is simply an increased series resistance on one input, while the other input is grounded via the same coupling cap but no series resistance. This is an unbalance that gave rise to plop noise.
Ok, never mind, lets do some sequencing around mute and SDZ and everything will be fine...
Nope! Sequencing requires a way of noiseless switching - and that is the problem...

With unbalanced inputs, toggling mute or SDZ input level even with stable supply voltage results in plopping, so there is no way to switch off noiseless in case of unbalanced inputs.

Conclusion
I do see no point in any sequencing of SDZ or MUTE inputs – as long as inputs are unbalanced. Any focus should be on perfect input impedance balance.
Click to expand...
I can't guarantee perfect input impedance balance because the end user determines that, unless I do something like put an active buffer on the front end of this amp - which I'd need negative voltage to power. Even if the input impedance is perfectly matched, the tolerance of the input coupling caps will cause them to charge at slightly different rates so you'll still get a bit of a pop. It's not an easy problem to solve perfectly.

With SDZ high and MUTE high, the input stage of the TPA is enabled and the input caps will charge, provided you don't drop lower MUTE until the voltage across the caps is settled you won't get a bang. I've bench tested this.
 
I

irribeo

Member
Joined 2013
Oh I assumed this was only about power off plop, because power on plop is virtually non existant with many other boards like audiobah/sure3116/giancarlo mod, just power off plop isn't taken care off in any, just manual switch for sdz to put in standby befor removing power works and the remotecontrolled chinese board does complete startup and powerdown into standby with a little timer, completely silent, no connection to mutepin on that board just sdz. But removing power while idle not standby has plop like all other boards I know.

(maybe tpa3125? all SE?)
 
doctormord

doctormord

Member
Joined 2007
360customs.de
rsavas said:
So all my ideas are not the best, at least I am contributing!!

I actually take offense to unnecessary statements such as these as they add constructively NOTHING to the conversation.
"gmarsh" shows class, a fine Canadian, which you two seem to lack and he also gives a valid reason why it is not necessary or worthy of inclusion.
You guys are akin to a bunch of bullies that want to kick someone, when they are down. GROW UP CHILDREN!!
Click to expand...


I don't get it. You state, you worry about switching noise and I asked "wtf", because i can't imagine a problem with it. You said nothing about, why you worry about. Maybe from your own exoerience? Why don't you share you experiences, but "bash" people here for nothing?

And please stop shoutin around...

Regards.
 
doctormord

doctormord

Member
Joined 2007
360customs.de
rsavas said:
Interesting observations.
TPA32xx? What is the exact part number and on what board/design?
That is not my experience with the TPA3100D2. .
Click to expand...


The doctormord board:
http://www.diyaudio.com/forums/showthread.php?t=251859


attachment.php
 
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gmarsh

gmarsh

Member
Joined 2004
OK, finally got the BOM together. I'm back to 100% parts available from Mouser.

Assuming I get orders for 25 fully built cards... before taxes, the 'official' BOM cost excluding PCB is $39.09 CAD. With "tax", $51.50 - adding $8 for the PCB we're basically at 60 bucks. Add 25 bucks assembly for a full one, 85 bucks CAD.

"tax" is parts cost + ($50 shipping/duty + $60 test jig cost)/orders + 15% HST.

I'll throw together the group buy thread shortly, and create the BOM on the Mouser site.
 
gmarsh

gmarsh

Member
Joined 2004
Got the BOM created on Mouser, looks like I can e-mail it to people but not make it publicly shareable easily. I'll e-mail it to whoever wants to have a peek. Building qty 1, the BOM cost on the Mouser site is $57.56 CAD before taxes.

Terminal blocks are Phoenix 1984675 (8 position) and 1935200 (6 pos). These are pretty decent screw type ones, I had top of the line rising cage blocks designed in previously but changing to this type shed $7/card at qty 25.

Decoupling is 470uF/35V UCC KZM, 82uF/35V OSCON, and three MLCC's per channel. Change/substitute the aluminum parts at will but I'd leave the MLCC's alone, the 10uF/50V Murata is selected because it only drops 40% of its capacitance at 25V.

Output filter film cap is Epcos B32529C684J, 5%/0.68uF/63V. Kemets can be had for a couple pennies less, Wima's for a few dimes more. Output filter inductor is Ice Components 1D14A-100M, which doesn't have any drop-in alternatives but it's a damn good part for this application, you can always airwire in something else if you want.

Input coupling cap is Epcos B32529D225J, 5%/2.2uF/63V.
 
infinia

infinia

Member
Joined 2005
a couple of lead acid batteries taken "off line" for solar charging.
or something V regulated.
Meanwell half frame SMPS, might work but maybe some issues grounding , common mode noise etc best get some users that have had actual success in "systems" similar to yours.
 
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gmarsh

gmarsh

Member
Joined 2004
cogitech said:
What do you smart folks consider to be the better P/S choice for this specific design?

Linear or SMPS, and why?
Click to expand...
As long as the voltage doesn't exceed 25-26V (which can trip the OVP in the TPA) and the power supply is stable with ~1200uF of low ESR capacitance placed on its output if it's a regulated one, I'd say either one is OK.

If you're buying a switching supply, buy a known brand from a known distributor. Personally I'd buy a Delta or TDK from Digikey, or a Mean Well from Mouser. I don't trust anything sold on eBay that plugs into AC.
 
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