Hi Team
As we have used AD1937 in our design we would like a technical team to review and give a feed back on it.

Kindly help us in this regards.

Question

Hi Team As we have used AD1937 in our design we would like a technical team to review and give a feed back on it. 
 Kindly help us in this regards. 
 I have attached schematics file for your reference. 
 PDF

DaveThib · Accepted Answer

Hello Irshath, 
 Thank you for allowing us the opportunity to review the design before you build the first unit. 
 I noticed a discrepancy on the bypass caps. You have four 0.1uf caps on the +3.3A voltage line but there are only two DVDD power pins and you have two 0.1uf caps on the V3P3_AUD voltage rail but there are four AVDD power pins. So I think these are backwards. Move two of the 0.1uf caps over to the AVDD pins. Each pin requires its own bypass cap. 
 
 You are missing the loop filter for the PLL. You must have it. This is the LF pin, pin 61. See the datasheet for values and how to connect the filter. It does not go to ground. 
 
 You have the P_D/RST pin defaulted to be pulled low. This will hold the part in reset. So pull that line high and you should put a 0.1uf cap on the pin as well since you have a rather high impedance 4K7 resistor to pull it up. So you do not want noise to trigger a reset. So stuff R2531 and DNS R2530 
 
 Analog Ground and Digital Ground... This is a tricky subject and I have seen this from several different angles. You can certainly try to do what you suggest with tying the two grounds at one point. However, inside our part the two grounds are tied but not exactly zero ohms. It is best to have one ground plane for the entire circuit around the codec. You can choose to use an analog ground for the OpAmps since they are operating differential on the input side. What will be VERY important is the PCB layout. Properly connecting the bypass caps to the pins and planes and then controlling and ground fill on the top layer to keep it away from the ground pins and to not tie to the bypass caps before the connections to the planes. This document details all this. I strongly recommend you follow my recommendations. 
 (+) PCB Layout Best Practices for AD193x codecs - Q&A - Audio - EngineerZone (analog.com) 
 
 By the way, I was in Bangalore this past summer! Lovely city. It helped me to not complain as much about the traffic in Boston. 
 
 Dave T)

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Hi Team As we have used AD1937 in our design we would like a technical team to review and give a feed back on it. Kindly help us in this regards.