ADAU1701 Eval board
Thread Summary
The user is building an ADAU1701 eval board and asks if 100mW resistors can be used instead of 63mW, whether to avoid vias for signals, and if specific GND connections should go directly to the ADAU1701. The final answer confirms that 100mW resistors are acceptable, advises minimizing vias for signal integrity, and specifies that GND connections should be kept as short as possible, ideally directly to the ADAU1701. The accompanying answer clarifies that both 56nF and 5.6nF capacitors can be used for the output DAC filter, as the RC combination results in the same cut-off frequency of 50.57 kHz. There is also a question about the correct DVDD voltage, which is 1.8V according to the data sheet, but 5V in the eval board documentation.AI Generated Content
Hi,
I am trying my hands on building a adau1701 eval board with the help of available schema on the website (EVAL-ADAU1701MINIZ).
My question is about the resisters. All the resisters on the board are 63mW. However I am finding 100mW registers easily available instead of 63mW. Is is ok to use 100mW resisters instead of 63mW?
My other question is, are there any specifications regarding vias? I am trying to avoid vias for signals as much as possible. Are there any specific connections where i must avoid vias?
Also, are there any specific GND connections which must to directly go to ADAU1701 device instead of common GND connection?
Thanks you in advance.
-Mayuresh
Audio Signal Processors
hardware
eval-adau1701miniz
SigmaDSP Audio Processors
adau1701
Adding to my earlier question. I am also uncertain as if which capacitor I should use for output DAC C13/14, 56nf or 5.6nf?
Eval schema
Device schema
On https://www.analog.com/media/en/technical-documentation/data-sheets/ADAU1701.pdf it says :
AVDD = 3.3 V,
DVDD = 1.8 V,
PVDD = 3.3 V,
IOVDD = 3.3 V,
However under EVAL-ADAU1701MINIZ.pdf it says (page 7):
WRITEBACK TRIGGER TRANSISTOR
The writeback trigger transistor circuit is intended to send a high pulse to the ADAU1701 WB pin when the power supply (DVDD) is interrupted. During normal operation, DVDD is high (+5 V), so Transistor Q2 is always turned on, and the WB signal is held low.
Not sure if DVDD is 1.8V or 5V, which is correct?
Hello Mayuresh,
You must consider the combination of R and C.
In the EVAL diagram R = 56.2 Ohm and C= 56 nF.
The -3dB point or cut-off frequency of this low pass filter equals 1 / ( 2 * PI * R * C ) = 50.57 kHz.
The filter in the data sheet uses R= 560 Ohm and C = 5.6 nF.
Since R is ten times larger and C is ten times smaller, the outcome is the same: 50.57 kHz.
So it doesn't really matter what you use.
Hi ODJ ..
Thank you for the revert. Its helpful.
I have already received my 1st board but it didn't work as expected, so a new board is under development. If someone can also help me with the voltage related question, it would be helpful.
Thanks again
-Mayuresh
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