How to reduce mistach in CMOS analog IC design?

• Nov 13, 2004

• #1

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leonken

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How to reduce mistach in CMOS analog IC deisgn ,especially for current source, bandgap voltage reference design?
Thank you

 

• Nov 13, 2004

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yargo

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Some basic rules:

1. Increas the size of the devices to be matched
2. Use simmetric layout
3. Replicate the same geometry using series/parallel connection to achieve the wanted size.


Bye

 

• Nov 13, 2004

• #3

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mylihua

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hi
use can pcell establish the same geometry . you can look at on "ic mask design" book!

 

• Nov 13, 2004

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zmliu

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Refer to Razavi and Martin's classic books.

 

• Nov 13, 2004

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Sergiu_Q

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mylihua said:

hi
use can pcell establish the same geometry . you can look at on "ic mask design" book!

Click to expand...

Hi
Where I can find this book?
I don't find it on this site....can upload this book for us?

 

• Nov 14, 2004

• #6

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sunking

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Another:

Use dummy device

 

• Nov 15, 2004

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CDRCDR

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For current source,use cascode architecture, or use source series resistor to improve matching.

 

• Nov 15, 2004

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leonken

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sunking said:

Another:

Use dummy device

Click to expand...

Where I can find some documents about the dummy device application?
Thank you!

 

• Nov 15, 2004

• #9

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leonken

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CDRCDR said:

For current source,use cascode architecture, or use source series resistor to improve matching.

Click to expand...

Can you give me some links about such topic?
Thank you

 

• Nov 15, 2004

• #10

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wmlaketahoe

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draw them in same orientation

 

• Nov 15, 2004

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terryssw

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I have a questions: What condition for the matching parameters Avt and Ak based on? Is it based on just two same structure spaced closed to each other (without interdigit), or stands Avt for interdigit or common-centroid one? For example, if datasheet say Avt = 1% um, will common-centroid layout improves this level of matching?

 

• Nov 15, 2004

• #12

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jebi

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Utilize degen resistor to help match, passive devices should have better
matching performance than active device, due to simpler process.

 

• Nov 15, 2004

• #13

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Hughes

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"The Art of Analog Layout" discusses much about device matching. This book can be download from this site.

 

• Nov 15, 2004

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emilian6

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Yes, "The Art of Analog Layout" is really good for understanding the basics of matching. Here is the link:

 

• Nov 15, 2004

• #15

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melodyseu

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common centriod structures, see to 'The art of analog design'