jmf11
Active Member
Hello,
I'm working on a multichannel USB to I2S bridged based on stm32 and a simple multi-channel DAS (exES9080). Project is there: https://www.diyaudio.com/community/...lti-channel-hardware-part.414128/post-7735757.
Browsing the forums, I see that many pay some attention to the noise propagation between the USB (especially in case of USB powering the device), and the analog part.
I'm not looking at the ultimate performance, but doing it right and addressing well at least the first order items. I understand that noise from USB can creep from VBus power, and data lines. I'm looking for information on the orders of magnitude of the different contributors and "noise path" to the DAC output. Intention is to tackle the most important things first.
I understand that first of all I need high PSSR LDO for the different parts: MCU, clocks, DAC
Example: it may not make sense to have dedicated power supply for the module if noise from USB data lines or onboard MCU are on par with noise from Power rail...
Would it make sense to have a dedicated basic switching power supply compared to using the convinient Vbus 5V? Will what I will get from a phone charger be better from the Vbus 5V?
Once VDD is done correctly, what couls be the expected impact of digital isolators on data lines to the DAC?
Are there some important noise passive filtering not to miss in the system?
Documents, studies, measurements, advices warmly welcomed.
Best regards,
JMF
I'm working on a multichannel USB to I2S bridged based on stm32 and a simple multi-channel DAS (exES9080). Project is there: https://www.diyaudio.com/community/...lti-channel-hardware-part.414128/post-7735757.
Browsing the forums, I see that many pay some attention to the noise propagation between the USB (especially in case of USB powering the device), and the analog part.
I'm not looking at the ultimate performance, but doing it right and addressing well at least the first order items. I understand that noise from USB can creep from VBus power, and data lines. I'm looking for information on the orders of magnitude of the different contributors and "noise path" to the DAC output. Intention is to tackle the most important things first.
I understand that first of all I need high PSSR LDO for the different parts: MCU, clocks, DAC
Example: it may not make sense to have dedicated power supply for the module if noise from USB data lines or onboard MCU are on par with noise from Power rail...
Would it make sense to have a dedicated basic switching power supply compared to using the convinient Vbus 5V? Will what I will get from a phone charger be better from the Vbus 5V?
Once VDD is done correctly, what couls be the expected impact of digital isolators on data lines to the DAC?
Are there some important noise passive filtering not to miss in the system?
Documents, studies, measurements, advices warmly welcomed.
Best regards,
JMF