Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

why not series pip cap?

Status
Not open for further replies.

rightmederek

Junior Member level 1
Joined
Sep 10, 2013
Messages
16
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
100
Hi all,

I never see any ic using series pip cap, why is that?

Thanks,
DD
 

dick_freebird

Advanced Member level 5
Joined
Mar 4, 2008
Messages
6,912
Helped
2,024
Reputation
4,052
Reaction score
1,864
Trophy points
1,393
Location
USA
Activity points
55,356
You need a dual poly process and this is not that common,
it used to be a way to go in mixed signal CMOS but I think
people have moved to MIM caps as better Q and more
latitude in placement can be had (e.g. poly cap means
no CMOS structures coincide, while a higher-layers MIM
can be placed over active devices if planarity is good).
POP / PIP caps also have higher series resistance / lower
Q, and have higher parasitic C on the bottom plate owing
to proximity to the substrate plane.
 

rightmederek

Junior Member level 1
Joined
Sep 10, 2013
Messages
16
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
100
You need a dual poly process and this is not that common,
it used to be a way to go in mixed signal CMOS but I think
people have moved to MIM caps as better Q and more
latitude in placement can be had (e.g. poly cap means
no CMOS structures coincide, while a higher-layers MIM
can be placed over active devices if planarity is good).
POP / PIP caps also have higher series resistance / lower
Q, and have higher parasitic C on the bottom plate owing
to proximity to the substrate plane.
thanks, but is using it in series possible?
 

erikl

Super Moderator
Staff member
Joined
Sep 9, 2008
Messages
8,112
Helped
2,685
Reputation
5,350
Reaction score
2,284
Trophy points
1,393
Location
Germany
Activity points
44,153
... is using it in series possible?
Actually, yes, with double poly PIP this should be possible. But only for achieving an even lower cap value than you would get with a single min. PIP structure (and why would you need such a small cap?). In such case use a symmetrical serialization, i.e. (P1-P2)---(P1-P2), to avoid parasitic asymmetries.

But do not use this concept to achieve high voltage caps! Voltage between P1 & substrate is limited, s. max. FOX (field oxide) voltage.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top