for ADAU1961 Design
For these signals you do not have to maintain a target impedance. On the product page there is a link to an IBIS file that you can import into signal integrity modeling programs. Then you can import the specifics of your PCB layout and optimize it for the best signal integrity. The IBIS model we have was created from actual measurements of the part and not from simulations. It is good that you are paying attention to this early in your design phase.
Here is a link to the product page:
We are using ADAU1961 in our design. We are using RHP,LHP and MONOOUT mode signals in the analog side. And SDI, SDO, LRCK, SCK, MLCK & MIC detect signals to interface with our USB Hub IC. I need your help to get the below answers. Please reply.
Attached the SCH what we are using. do you see any improvement for this?
We are planning to do the below in the PCB , is there anything else to be taken care?
o 4 layer, 1.6mm thick, Stackup = Top, GND, Power and Bottom layer.
o Direct 5V adaptor to power up the board and MCP1826 –LDO for3V3
o Separate split power and Gnd plane for ADAU1961 and will be connected to board power and GND through a 0805pkg (FB for Power /Res for GND)
o Bypass cap placement and routing as given in the ADAU1452 datasheet
o AD to Audio jack will be routed with minimum distance and cu pour in same layer with multiple vias and with proper GND return path in adjustment layer.
o Digital lines 50 ohm impedance and resister on all digital lines
Our aim is to arrive better SNR value (90dB or above). Do you think the above will work out for getting 90dB?
What is the best SNR value can be arrived using ADAU1961 (is there any link or pdf)
It may also make sense to add a damping resistor near the source end of each signal -- typically about 22 - 47 ohms. For an example, see:
Damping Resistor(s) for MCLK Distribution
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