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Analog and Digital Ground - What are the differences

 
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newbieinelectronics



Joined: 02 May 2008
Posts: 9


Post09 May 2008 14:54   Analog and Digital Ground - What are the differences

Hi.

I would like to know what is the difference between analog and digital ground.

How do I connect them?

Can you please point me some books about it?

Thanks.
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zhongdg



Joined: 03 Apr 2008
Posts: 79
Helped: 6


Post09 May 2008 15:12   Re: Analog and Digital Ground - What are the differences

Analog ground is for analog block and has less noise.
Digital ground is for digital block. The noise is very big.
So it's better to seperate and connect it at board level.
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newbieinelectronics



Joined: 02 May 2008
Posts: 9


Post09 May 2008 15:20   Re: Analog and Digital Ground - What are the differences

Hi. Thanks for your answer.

But I still have some doubts:

1 - Supose that my circuit has analog and digital parts and I have a power supply. How can I separate the analog and the digital ground if they have the same power supplier?

2 - How do I connect them at board level?

Do you know any documentation that I could read ?
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davidgrm



Joined: 08 Apr 2006
Posts: 187
Helped: 18


Post09 May 2008 16:25   Re: Analog and Digital Ground - What are the differences

You would usually have two voltage regulators, one for the analogue and one for the digital devices. The two grounds would be connected together at the ground pins of the regulators. You would use a ferrite bead or a choke to make this join, this will filter out noise. The type and value of the device depends on the frequency's involved.
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Miguel Gaspar



Joined: 06 Mar 2006
Posts: 386
Helped: 36
Location: Culiacán, Sinaloa, Mexico


Post10 May 2008 18:26   Analog and Digital Ground - What are the differences

Another way to reduce noise is to put a capacitor en each digital chip about 0.1uF. Or put a choke betwen the voltage regulator and the digital devices.

Good luck
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ckshivaram



Joined: 21 Apr 2008
Posts: 323
Helped: 22
Location: korea


Post27 May 2008 6:26   Re: Analog and Digital Ground - What are the differences

http://www.sigcon.com/Pubs/news/7_02.htm
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newbieinelectronics



Joined: 02 May 2008
Posts: 9


Post27 May 2008 23:50   Re: Analog and Digital Ground - What are the differences

ckshivaram, this link is very good.

Thanks.
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