Dec 14, 2005 #1 G gsheng Junior Member level 2 Joined Jan 12, 2005 Messages 20 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,283 Activity points 146 when PD/ND mode, there are two paths from pad to Vdd, (1) PAD->NMOS->VSS->VSS ESD BUS-> Vdd to Vss NMOS(or diode)->Vdd; (2) PAD->foating well of PMOS ->Vdd; I don't know which path is the main path. does path 2 exist?
when PD/ND mode, there are two paths from pad to Vdd, (1) PAD->NMOS->VSS->VSS ESD BUS-> Vdd to Vss NMOS(or diode)->Vdd; (2) PAD->foating well of PMOS ->Vdd; I don't know which path is the main path. does path 2 exist?
Dec 14, 2005 #2 S sunking Advanced Member level 3 Joined May 25, 2004 Messages 873 Helped 70 Reputation 140 Reaction score 23 Trophy points 1,298 Activity points 6,283 why not add a pmos for the charge from PAD to Vdd?
Dec 14, 2005 #3 G gsheng Junior Member level 2 Joined Jan 12, 2005 Messages 20 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,283 Activity points 146 Because the pad is like 3.3V torlance 5V PAD. Added after 2 hours 5 minutes: We can not only connect PMOS's bulk to core vdd. Otherwise it will leackage through juntcion diode.
Because the pad is like 3.3V torlance 5V PAD. Added after 2 hours 5 minutes: We can not only connect PMOS's bulk to core vdd. Otherwise it will leackage through juntcion diode.
Dec 14, 2005 #4 B Baiyawfan Newbie level 5 Joined Dec 9, 2005 Messages 8 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,346 I think if PAD has a negtive ESD voltage,then path (1) is active,else if postive voltage,path (2) is active,right?
I think if PAD has a negtive ESD voltage,then path (1) is active,else if postive voltage,path (2) is active,right?
Dec 14, 2005 #5 R ranier Junior Member level 1 Joined Aug 24, 2005 Messages 18 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,283 Activity points 1,446 In case of tolerant I/O ( floating nWell structure), there is no path of pad to vdd . so path (1) is just available.
In case of tolerant I/O ( floating nWell structure), there is no path of pad to vdd . so path (1) is just available.
Dec 15, 2005 #6 G gsheng Junior Member level 2 Joined Jan 12, 2005 Messages 20 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,283 Activity points 146 ranier said: In case of tolerant I/O ( floating nWell structure), there is no path of pad to vdd . so path (1) is just available. Click to expand... Do you mean path(2) is available? I do want to know why?
ranier said: In case of tolerant I/O ( floating nWell structure), there is no path of pad to vdd . so path (1) is just available. Click to expand... Do you mean path(2) is available? I do want to know why?