Buffered FET logic, Direct coupled FET logic tutorial
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From: Daku on 11 Aug 2010 03:45 Could some electronics guru provides some URLs for authentic buffered FET logic and/or direct coupled FET logic ? Thanks in advance.
From: Tim Williams on 11 Aug 2010 11:13 Google "74HC application note". 74HC is always buffered (but there is the occasional 74HCU which is specifically unbuffered). Ditto for 4000 series logic, CD4001BE is buffered, -UBE is unbuffered. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms "Daku" <dakupoto(a)gmail.com> wrote in message news:2f106665-962a-445b-a176-5f856faab9dc(a)o7g2000prg.googlegroups.com... > Could some electronics guru provides some URLs for authentic buffered > FET logic and/or direct coupled FET logic ? Thanks in advance.
From: John Larkin on 11 Aug 2010 14:20 On Wed, 11 Aug 2010 00:45:25 -0700 (PDT), Daku <dakupoto(a)gmail.com> wrote: >Could some electronics guru provides some URLs for authentic buffered >FET logic and/or direct coupled FET logic ? Thanks in advance. Like GaAs DCFL, the GigaLogic stuff? That was depletion load, I think, like old-old NMOS stuff. Power hog. John
From: Tim Williams on 11 Aug 2010 15:37 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:gcq566pvub8jtqbtirn8oiu6s0rbt5ge1s(a)4ax.com... > Like GaAs DCFL, the GigaLogic stuff? That was depletion load, I think, > like old-old NMOS stuff. Power hog. Yuck, GaAs logic. It sounds like a good idea, until your signal has to change back. Silicon PMOS aren't terrible, good enough to make high speed CMOS with. They're almost impossible to find discrete though. I haven't been able to find a P type 2N7002 for the same price. The suckiness of PFETs is directly related to the bandgap. Silicon is moderate, so PFETs are okay. GaAs and GaN make shitty PFETs. I can only imagine how poorly SiC and diamond PFETs will work, when they come along. I suppose they may already exist in the laboratory, I don't know. Curiously, this seems to imply that Ge-CMOS would be quite nice indeed, but the leakage is something else. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: markp on 11 Aug 2010 16:14
"Tim Williams" <tmoranwms(a)charter.net> wrote in message news:XZC8o.1154$co1.1062(a)newsfe11.iad... > "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in > message news:gcq566pvub8jtqbtirn8oiu6s0rbt5ge1s(a)4ax.com... >> Like GaAs DCFL, the GigaLogic stuff? That was depletion load, I think, >> like old-old NMOS stuff. Power hog. > > Yuck, GaAs logic. It sounds like a good idea, until your signal has to > change back. > > Silicon PMOS aren't terrible, good enough to make high speed CMOS with. > They're almost impossible to find discrete though. I haven't been able to > find a P type 2N7002 for the same price. You mean PMOS as in P-channel MOSFET? Is that enhancement mode? There are certainly quite a few P channel enhancement mode MOSFETs around, I tend to use the BSS84 as a P-channel equivalent of the 2N7002. They are pretty close in price, certainly not significantly more, and multi-sourced. > > The suckiness of PFETs is directly related to the bandgap. Silicon is > moderate, so PFETs are okay. GaAs and GaN make shitty PFETs. I can only > imagine how poorly SiC and diamond PFETs will work, when they come along. > I suppose they may already exist in the laboratory, I don't know. > Curiously, this seems to imply that Ge-CMOS would be quite nice indeed, > but the leakage is something else. > > Tim > |