All, I am currently working with a PCB DUT board that interfaces to an ATE (tester). I am using this board along with a single socket to measure power MOSFET DC characteristics. The PCB is a simple 4 layer board that routes the force/sense resources of the tester to the MOSFET socket. I currently do not know the exact layer stackup of the board since I merely created the schematic, and the layout was done elsewhere. I do know that there are a set of force and sense traces on the board for 5 individual tester resources. 1 resource connects to the gate, 3 resources to the drain, & 1 resource to the source(source is also tied to ground). There are also some digital traces on the board that bring digital power for the EEPROM and the relays, and these have tantalum and electrolytic capacitors included. Everything on the board, analog and digital are using 1 single point ground. My problem is when I am trying to measure off-state leakage from drain to source of the MOSFET (Vgs =3D 0V, Vds =3D 55V), I measure >200nA of current before I even put the device in the socket. When I repeat the measurement with a blank PCB board I measure 20nA, so I don't believe that it is coming from the tester or cables. The tester resource that I am using for the measurement has accuracy & resolution <100pA. Any ideas of where this 200nA leakage current may be coming from? Thanks, Chris Infineon Technologies ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu