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Design >> Mixed-Signal Design >> GNDs for Analog & Digital
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Message started by Vishwanath M on Aug 8^th, 2005, 4:36am

Title: GNDs for Analog & Digital
Post by Vishwanath M on Aug 8^th, 2005, 4:36am

Hi,

I have digital & Analog blocks sitting on the same die. Problem is to connect ground (Gnd) for digital & Analog.

Could u please tell the Advantages & Disadvantages of having the Configurations in terms of noise, etc..

1. Connect seperate DGnd & AGnd.
2. AGnd for Digital & Analog
3. DGnd for Digital & Analog.
4. take Seperate Gnd for Digital & Analog then go for shorting in the board level (PCB).

Thanks in advance.
Vishwanath M

Title: Re: GNDs for Analog & Digital
Post by Paul on Aug 8^th, 2005, 9:39am

Vishwanath,

in order to discuss this topic, it is important to know whether your design is integrated on a high- or low-resistivity substrate. Simply check whether you are using an epi process or not.

Maybe you could also mention the operating frequencies of digital and analog part, as well as the sensitivity of analog (high-resolution converter and RF vs. low-resolution blocks).

In the meantime, you can already have a look at the following document:
http://www.specctra.de/whitepapers/sca443.pdf

Paul