rkn80

DIY AD-converter build help thread
« on: May 31, 2010, 09:55:43 AM »
Hi,

the intention of this thread is to help peple with building their ADc from the group buy. I'm not going to discuss design questions here instead the topics should be more related to practical aspects.
So if you have problems or questions post it here. Maybe I or someone else can give you a hint or help you.

Raphael


Minotaurus

Re: DIY AD-converter build help thread
« Reply #1 on: May 31, 2010, 04:05:15 PM »
Is there a possibility to still get the pcb's ?

rkn80

Re: DIY AD-converter build help thread
« Reply #2 on: June 01, 2010, 03:32:21 AM »
Here you find a HowTo for soldering the TQFP case:
http://thomaspfeifer.net/ => Link: "Anleitung zum SMD löten: TSOP"

Raphael

Re: DIY AD-converter build help thread
« Reply #3 on: June 02, 2010, 05:05:00 AM »
Hi

Got a question concerning the PCM4204. In the TI datasheet it is mentioned that the thermal pad has to be soldered on the board. Now with a normal solder iron that everyone of us uses, i guess it's pretty impossible to do.
So how about making this connection ? Or is it ok to only solder the pins of the chips and push the chip on the thermal pad without soldering ?

Flo

mhelin

Re: DIY AD-converter build help thread
« Reply #4 on: June 03, 2010, 02:12:13 AM »
Hi

Got a question concerning the PCM4204. In the TI datasheet it is mentioned that the thermal pad has to be soldered on the board. Now with a normal solder iron that everyone of us uses, i guess it's pretty impossible to do.
So how about making this connection ? Or is it ok to only solder the pins of the chips and push the chip on the thermal pad without soldering ?

Flo

Don't know but you can solder the pad from the back side of pcb through a hole. Instructions you will find here:

http://hobbymechatronics.com/component/content/article/32-electronics/12-diy-smt-soldering-using-standard-equipment
« Last Edit: June 05, 2010, 04:53:06 AM by mhelin »
Mikko

rkn80

Re: DIY AD-converter build help thread
« Reply #5 on: June 03, 2010, 03:51:29 AM »
The last instruction is a very good one. Please note that you then have to drill a bigger hole into the thermal pad.
Another option is to put some  heat-conductive paste on the thermal pad before you put the chip on it. Then you have to press the chip on the PCB when you fix it by soldering some pins like in the instruction. I did hat already with success. Because for the PCM4204 the thermal pad only connects the pcb as a heatsink to the chip. But if you want to feel good you can still connect the pad with some thin wires to ground. ;)

Raphael

Andy Peters

Re: DIY AD-converter build help thread
« Reply #6 on: June 04, 2010, 12:41:58 AM »
Got a question concerning the PCM4204. In the TI datasheet it is mentioned that the thermal pad has to be soldered on the board. Now with a normal solder iron that everyone of us uses, i guess it's pretty impossible to do.
So how about making this connection ? Or is it ok to only solder the pins of the chips and push the chip on the thermal pad without soldering ?

Use solder PASTE on the large PCB pad to which you attach the thermal pad. Use a hot-air rework tool with a nozzle designed for that chip size. Set the temperature and airflow such that the solder paste melts but the board doesn't scorch. It might help to use a heater block or a hot-air bath from below the board, too.

-a
"On the Internet, nobody can hear you mix a band"

Re: DIY AD-converter build help thread
« Reply #7 on: June 04, 2010, 12:45:31 PM »
Thanks for all the infos.

Flo

rkn80

Re: DIY AD-converter build help thread
« Reply #8 on: July 12, 2010, 08:33:20 AM »
Here are some infos about the clocking scheme.
Every device needs a master clock and the two I2S clocks (LRCK, BCK). For a working system you need a master that generates the I2S clocks and all the other devices have to be slaves.
Because a clocking board is not available yet let's assume you are building a system with 4 ADC cards and 4 AESout cards. Now you select one ADC card and configure it as master. This device will generate the I2S clocks. All other ADC cards have to be slaves. Now supply the slave boards with the I2S clocks from the master. Make sure that the sample rate and format configuration are equal on all boards (see schematic and datasheet). The AESout boards are slaves per default.
Finally you need to supply the system with a master clock. Here you can use oscillators like those from tentlabs.com or others (you can later reuse the oscillator on the clocking board, so you don't waste money here). Which frequency you need depends of your personal setup. See the PCM4204 datasheet. There is a table for the correct settings and master clocks dependung on the desired sampling frequency.
General hint: Keep the clocking lines short and of the same length. Depending on your design it can happen that you get crackling in the sound due to a bad clock distribution (especially if yoou use cables). Here you should do the try-and-error-method to find the best way. If you connect many devices on the same clock lines it might be needed that you need additional buffers due to line capacitances. anyway I was able to connect 9 devices on one clock line without problems.
I hope this will help you when making the clock connections.

Raphael

guitarguy12387

Re: DIY AD-converter build help thread
« Reply #9 on: December 13, 2010, 02:19:40 PM »
Hey guys,

For those of you who didn't buy kits, where are you getting your PCM chips? They have been out of stock everywhere i look forever now!


Re: DIY AD-converter build help thread
« Reply #10 on: April 09, 2015, 11:05:13 AM »
Will I be able to send word clock signal from my Black Lion Mkii?


 

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