what is hotwell?

[Dmitriy Shurin]

Hi,
I am wondering what is hot well: is it nwell with floating voltage (i.e.
not connected to vdd) or something else?


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[S. Badel]

yes it is a well with a potential other than vdd or gnd.

"Dmitriy Shurin" <shurin@bgumail.bgu.ac.il> wrote in message
news:1cabee530a0ce2d7160a492c55264e91.106736@mygate.mailgate.org...

Hi,
I am wondering what is hot well: is it nwell with floating voltage (i.e.
not connected to vdd) or something else?


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

 

[fogh]

Dmitriy Shurin wrote:

Hi,
I am wondering what is hot well: is it nwell with floating voltage (i.e.
not connected to vdd) or something else?


Indeed, it s a well that is left floating, or that is connected to a

potential that does not garanty that the well-epi junction stays in reverse.

If parasitic (injected) current flow in the epi near that well, it
could forward bias the well-epi junction, then a latchup can occur. Some
metal line is going to vaporise and a nice bubble will appear in your
IC's passivation 8~{


For the utmost protection, do not connect the well to a power-supply
line that is subject to ground-bounce or IR-drop. Connect it to a
"clean" network of minimum-width metal1 (there is only uA flowing in
there) that goes directly to an analog power pad.
Also, you can identify what devices may inject in the epi, and isolate
them (guard rings, deep-trench).