diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Digital Line Level (http://www.diyaudio.com/forums/digital-line-level/)
-   -   Bragi, an Asynchronous ES9023 DAC with isolated I2S Input and Alps RK27 Volume pot (http://www.diyaudio.com/forums/digital-line-level/220139-bragi-asynchronous-es9023-dac-isolated-i2s-input-alps-rk27-volume-pot.html)

Neutrality 21st September 2012 08:37 PM

Bragi, an Asynchronous ES9023 DAC with isolated I2S Input and Alps RK27 Volume pot
 
2 Attachment(s)
A simple board based on the ES9023 DAC running asynchronously with an 50 MHz oscillator

It has isolated I2S inputs, Analog volume control with Alps RK27 Pot.

Bottom layer is a dedicated ground plane with no interruptions.

Should be supplied with 6 VDC, which is regulated down to 5 VDC by LT1763 for use with the ADuM5000 isolated DC-DC Converter powering the isolated I2S inputs and going to the 3 separate 3.3 VDC LT1761 regulators used for powering the ES9023 IC, ADuM3440 digital isolator and the 50 MHz oscillator.

Neutrality 22nd September 2012 08:54 PM

1 Attachment(s)
I did a few final touches to the board.

Shortened it 5mm, added a ferrite in the supply line just before the oscillator, put a few more GND vias in the board at critical places, reduced the size of the isolated I2S input ground plane area.

jean-paul 22nd September 2012 09:50 PM

Hi the more ES9023 DACs the merrier. I think it will perform better without the RK27 though (or add a simple buffer after it). Please add a bead to the power supply pin of ES9023 too and feed it 3.6 V.

Interesting that you use 10 F for the charge pump circuit. Did you already build it ?

Neutrality 23rd September 2012 11:06 AM

Quote:

Originally Posted by jean-paul (Post 3175095)
Hi the more ES9023 DACs the merrier. I think it will perform better without the RK27 though (or add a simple buffer after it). Please add a bead to the power supply pin of ES9023 too and feed it 3.6 V.

Interesting that you use 10 F for the charge pump circuit. Did you already build it ?

ES9023 should have no problem with a 20K pot. Adding a ferrite bead to the ES9023 supply is a good idea. 3.6V just gives 2Vrms out instead of 1.9Vrms, no big difference.

Havent built it yet, just designing.

The 10uF between Cn and Cp is not a value that I have fully decided on, it could be lower than that and probably should be.

jean-paul 23rd September 2012 11:52 AM

Just try the 3.6 V. You will like it better. The reason for this is not 1.9 versus 2 V.

About the RK27: the ES9023 has no problem with it but you will have a higher output impedance at normal volume. In practice it will be better to use the potentiometer at the receiving end. I have doubts if the RK27 is good enough for this application. My guess is that the DAC will sound better without it but that is easy to try out.

syklab 23rd September 2012 05:35 PM

Quote:

Originally Posted by Neutrality (Post 3173837)
A simple board based on the ES9023 DAC running asynchronously with an 50 MHz oscillator

It has isolated I2S inputs, Analog volume control with Alps RK27 Pot.

Bottom layer is a dedicated ground plane with no interruptions.

Should be supplied with 6 VDC, which is regulated down to 5 VDC by LT1763 for use with the ADuM5000 isolated DC-DC Converter powering the isolated I2S inputs and going to the 3 separate 3.3 VDC LT1761 regulators used for powering the ES9023 IC, ADuM3440 digital isolator and the 50 MHz oscillator.

Hi,
What is IC6 and IC7 ?

Neutrality 23rd September 2012 06:23 PM

Quote:

Originally Posted by syklab (Post 3175912)
Hi,
What is IC6 and IC7 ?

IC6 is ADuM3440 digital isolator, isolates the I2S inputs.

IC7 is ADuM5000 isolated DC-DC converter. Provides power to the I2S isolator on the input side.

However, Im revising the design, adding a few ferrites, tweaking the layout and part values.

Gone is IC7, it basically draws way too much current(about 33% efficiency) and according to the datasheet it could put out some nasty switching noise, which I do not want in my circuit.

So now the digital isolator has to be supplied with a separate 3V3 supply on the input side.

Neutrality 23rd September 2012 08:00 PM

1 Attachment(s)
And its done. :)

jean-paul 23rd September 2012 09:54 PM

You might want to use a large cap for the positive supply pin of ES9023. 100 F or more. If you are going to use connector blocks for the outputs (if only for testing) the pads for those must be moved somewhat to the left or you will have to mount the PCB with only 3 screws ;)

Neutrality 26th September 2012 07:37 PM

Quote:

Originally Posted by jean-paul (Post 3176211)
. If you are going to use connector blocks for the outputs (if only for testing) the pads for those must be moved somewhat to the left or you will have to mount the PCB with only 3 screws ;)

There is enough room for the connector blocks, no worries, done many boards before and I know what I am doing. :)


All times are GMT. The time now is 09:10 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2