VS1011E SOIC28 Design Considerations

Designing hardware that uses VLSI Solution's devices as slave codecs such as an external MP3 decoder chip for a host microcontroller.
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misolabs
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VS1011E SOIC28 Design Considerations

Post by misolabs » Fri 2015-11-06 20:50

Hi,
are there any special design considerations for a circuit that uses the SOIC version of the VS1011 instead of the smaller packages? As a home-brew developer this chip is my only option for adding hardware mp3 decoding to a web-radio project (especially as the SPE breakout boards all seem to be discontinued and hard to source). Does the fact that GBUF is not available make a difference for a project where I want to drive a 20W power amplifier? Is the level of RIGHT and LEFT still biased around 1.25V?

Cheers,
Jerome

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Panu
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Re: VS1011E SOIC28 Design Considerations

Post by Panu » Sat 2015-11-07 10:49

Hi!

Wow, I don't think we're even producing the SOIC version anymore. I'll answer your question, but first I'd like to try to nudge you into using the LQFP, which we, uhum.., actually consider an "easy to solder" package, as opposed to BGA, QFN or LFGA. We solder them by hand daily in the lab and it's not a problem if you have a professionally manufactured PCB. And you can get a PCB for something like $5 from oshpark.com, which I've used myself and been very happy.

So you could consider getting a small-tip head for your soldering iron, some very thin soldering wire and most importantly flux. Perhaps borrow some +3 reading glasses, breeth deeply and relax. Put some solder into one corner pad on the PCB. Take the IC with a pair of tweezers. Align it on the PCB. Heat the pin which is on the pad with the solder. Do not add any more solder. Two hands is enough for this job. With the tweezers, adjust the position of the IC so that the pin on the opposite corner is aligned properly on the PCB. Solder the opposing pin with a very small amount of solder wire. Check that all pins are aligned properly on the PCB. Then with a minimal amount of solder, solder the rest of the pins. You don't even need to add new solder on soldering iron for each pin, usually there's enough "attached" to the iron. Never heat the soldering wire directly with the iron; always heat the pad/pin junction and let the heat from the pad wet the solder and drag it to the pin. If you get too much solder on a pin, wet a multi-thread wire with some flux and use it to "suck" the extra solder from the pin. After completion, enjoy your new acquired skill. :D

Now the answer to your question. Indeed, the LEFT and RIGHT signals are biased around 1.23 volts. So you get a strong transition from zero to 1.23 volt at analog power-up. You should connect the LEFT and RIGHT to your power amp using the "Line Out" connection from the "Line In & Line Out" diagram for which you can see a link below in my signature. You need the RC filters which are in the diagram. Because you get the rather large power-up pop/click, you need to keep your amplifier switched off until you have switched on the IC.

Good luck!
-Panu

PS. Another option would be to buy one of our "Simple DSP Boards" which contain the necessary power, clock and analog circuitry and bring out the signals in a pin header. Product link: Buy 1063 Simple DSP Board from VLSI webstore. We have those boards for VS1053, VS1063 and VS8053.
Info: Line In and Line Out, VS1000 User interface, Overlay howto, Latest VSIDE, MCU Howto, Youtube
Panu-Kristian Poiksalo, VLSI Solution Oy

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pasi
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Re: VS1011E SOIC28 Design Considerations

Post by pasi » Mon 2015-11-09 12:15

Yes, we're producing the SOIC28 version of the vs1011e still. :D
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misolabs
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Re: VS1011E SOIC28 Design Considerations

Post by misolabs » Mon 2015-11-09 14:24

Right... now i'm almost disappointed, Panu made it sound so exciting I was tempted to give the tiny package a try ;) Might still do...
I followed your advice on the line-out analog audio output and came up with the attached circuit. Does this sound plausible to you? The amplifier BOB I am using already has a DC blocking stage, so I guess I can skip the one you proposed? Is the minimalistic channel mixer acceptable for a hifi quality setup?
Thanks for your prompt (and enthusiastic ;)) replies, it is much appreciated! I've been playing around with your mp3 decoder chips for some years now and it has been great fun.

Have a great day,
Jerome
Attachments
vesp_analog_path.png
vesp analog schematic
vesp_analog_path.png (42.19 KiB) Viewed 2123 times

misolabs
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Re: VS1011E SOIC28 Design Considerations

Post by misolabs » Mon 2015-11-16 11:18

No objections? Then I guess I can go ahead an design my PCB around this setup. Sorry for having bothered you, I am just starting to learn about analog audio electronics and not that confident yet...

Cheers
Jerome

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Panu
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Re: VS1011E SOIC28 Design Considerations

Post by Panu » Tue 2015-11-17 10:07

No objections, looks like you have it figured out. Depending on the amplifier, if you find some issue in frequency response, you can adjust the sizes of the capacitors.

-Panu
Info: Line In and Line Out, VS1000 User interface, Overlay howto, Latest VSIDE, MCU Howto, Youtube
Panu-Kristian Poiksalo, VLSI Solution Oy

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