In a message dated 10/30/2016 6:07:56 P.M. Eastern Daylight Time, davidwhess@gmail.com writes: That is always the danger when using parts for characteristics not guaranteed in the specifications. YES Sometimes a process just becomes obsolete necessitation new parts to be fabricated on a new process. Or a process may have enough variation that some lots or parts meet unguaranteed specifications and others do not. Occasionally a minor update is made to correct a problem or improve yield that significantly changes unguaranteed specifications. This was not the case with Infinion. They moved the production from Germany to Austria and did change the process.... And of course the company could be bought resulting in the process or parts you are relying on being discontinued. That is the reason why I / we will design or own transistors as other also do. There is a possibility that some oscillator producers will get into trouble .. This can happen with the crystals too I am currently worrying about this with Linear Technology being bought by Analog Devices and NXP being bought by Qualcomm. In the case of Qualcomm, I cannot see them being in the discrete parts business. As far as testing, nobody likes to test for noise or low leakage for that matter. Test time costs money and low frequency noise testing especially takes a lot of time. The example I like to use for this is the LMC6081 ($0.83) and LMC6001 ($5.76) operational amplifiers; the later is identical to the former except it spends a lot more time on the tester to guarantee its lower input bias current. Common small signal transistors are usually specified with 50 or 100 nanoamps of leakage even though it is often 1000s of times lower because that is as good as the automatic testers can do quickly. I use special set of test oscillators at different frequencies with rivets to connect the transistors. Before I forget this, the same is valid for diodes getting noisier. I have arranged to have a custom diode developed for us, in a foundry, Important point ! The R&S FSWP signal analyzer takes only few seconds to test all On Sun, 30 Oct 2016 17:06:52 -0400, you wrote: >It has to do with the manufacturing process and a reduction in cost. I can >not speak for other companies, Infinion "killed" the good phase noise >performance but the large signal noise is not specified in the data sheet so >they are legally "clean" > >>In a message dated 10/30/2016 4:56:38 P.M. Eastern Daylight Time, >>davidwhess@gmail.com writes: >> >>You mentioned suitable transistor availablity being an increasing >>problem and I have run across that myself. Do you expect Qualcomm's >>aquisition of NXP to have an impact? >> >>NXP is currently the best source I have for fast complementary pairs >>or even just fast PNPs. _______________________________________________ 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.