On 18 July 2015 at 04:25, Charles Steinmetz <csteinm...@yandex.com> wrote:
> Dave wrote: > > 1) Do you have any suggestions for a replacement for the LM394CN, which is >> obsolete and unobtainable from any reputable source? There are plenty on >> eBay for a few $'s from China, but the probability of them being fakes is >> greater than 0.99. The MAT12 seems to be one possible candidate for a >> replacement and while not cheap, is available from reputable sources like >> Farnell. >> > > The MAT12 should certainly work, but there is *plenty* of DC degeneration > in the circuit (1v at each emitter), so there is no advantage to matched > transistors. A pair of Zetex (Diodes, Inc.) ZTX849 or FZT849 actually have > significantly lower voltage noise than either the LM394 or MAT12. > > Best regards, > > Charles > Do you really mean the ZTX849? It is a power transistor (5A continuous current collector current, 20 A peak collector current), with no specification for noise on the data sheet. It would on the face of it hardly seem a wise choice for a low noise amplifier, but perhaps you know something I don't. The LM394CN or MAT12 are at least a low-noise devices, even if the matching between the two transistors in the package is not needed. Dave _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
