On 08/23/2017 10:22 AM, Jim Thompson wrote:> On Wed, 23 Aug 2017 04:35:58 -0700 (PDT), pcdhobbs@gmail.com wrote: > >>> Do you happen to have any data on the RF performance or gate leakage? >> >> I always run JFETs at about 2.5V D-S, to get full transconductance with minimal heating and no avalanche gate leakage. In that mode the CPH3910 has higher transconductance and lower capacitance than the BF862, and about the same leakage, i.e. a couple of picoamps at room temperature. >> >> BF862s run well at I_DSS, so I've sometimes used an op amp to adjust the tail current to zero out V_DS. That way you can take the output straight from the bootstrap if you like, and of course it's good for IR photodiodes that don't like reverse bias. >> >> With an I_DSS of about 30 mA vs around 12, CPH3910s run a bit warm at 0 V D-S, so it's less attractive to do that. >> >> Cheers >> >> Phil Hobbs > > V_DS?? You mean V_GS??Yes, of course, thanks. I said V_DS was 2.5V. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
BF862 discontinued?
Started by ●August 22, 2017
Reply by ●August 23, 20172017-08-23
