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https://designers-guide.org/forum/YaBB.pl Design >> High-Power Design >> LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process https://designers-guide.org/forum/YaBB.pl?num=1434531720 Message started by xlowen on Jun 17th, 2015, 2:02am |
Title: LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process Post by xlowen on Jun 17th, 2015, 2:02am Hi Guys, I am using TSMC 0.18 BCD process to design a HV ADC. the PDK I got from TSMC only gives example on how to put two 1.8V NMOS devices into one isolation ring. When I put 1.8V pmos & nmos into one isolation ring like I showed in the attached slides, however, the LVS reports an error (diode called nwdio_iso is missing in the schematic). Can anybody give some feedback on this issues? The reason I want to share isolation ring between LV nmos & pmos is I want to isolate a LV folded cascode ampifier for noise consideration. Thanks! |
Title: Re: LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process Post by boe on Jun 18th, 2015, 9:01am Xlowen, does your LVS rule file extract and compare parasitic diodes? - B O E |
Title: Re: LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process Post by xlowen on Jun 18th, 2015, 12:18pm Hi Boe, Thanks for your reply. Yes, I enabled the option to extract parasitic diodes. I guess the 1.8V PMOS can not be generated based on HV NWell/NBL. Otherwise, the LVS should not give that error: "parasitic diode nwdio_iso (which is between 1.8V NW and PSUB) is missing." Thanks xlowen |
Title: Re: LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process Post by boe on Jun 19th, 2015, 4:26am xlowen, then you need the parasitic diodes (e.g. between the wells) in the schematic as well. - B O E |
Title: Re: LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process Post by boe on Jun 19th, 2015, 7:07am xlowen wrote on Jun 18th, 2015, 12:18pm:
- B O E |
Title: Re: LV devices isolation in TSMC 0.18 high voltage BCD Gen2 process Post by xlowen on Jun 20th, 2015, 2:56am Hi Boe, I am just confused by the PDK I got from TSMC. In one document, the LV isolation is like fig1, for this case, two parasitic diodes(PW/NBL & NBL/PSUB) are added in the schematic below by myself, the other shows LV isolation like fig2, in which three diodes(NW/PW & PW/NBL & NBL/PSUB) are required. from LVS results I got, it seems the latter one is correct. xlowen |
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