katrin
Joined: 03 Dec 2005
Posts: 101
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 15 Apr 2007 20:23 Different Diodes in CMOS technology? |
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The design kit (CMOS AMS) provides three different kinds of diodes
1, nwell on Psubstrate
2, p diffusion on Nwell
3, n diffusion on Psubstrate
Now I want to design ESD protection circuit, therefore, i need to implement the diodes
from pad to Vdd and ground.
I am confused about which diode can I select ?
At the same time, the design kit offers just the symbol. but no layout for the diodes. Do I need to draw the layout by myself, or can I ask the foundry for help?
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littlej_zju
Joined: 05 Dec 2006
Posts: 9
Helped: 2
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| 16 Apr 2007 6:19 Different Diodes in CMOS technology? |
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Usually, P+/Nwell is used for Vdd-Vss ESD protection diode. For P+/Nwell diode, Nwell tied Vdd and P+ tied gnd, thus there is minimum leadage between Nwell and Psub (tied gnd).
As for layout, you can ask foundry to provide examples.
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