Found a source of Linear Systems FETs and Pico Amp Diodes - Page 1
Forum section: electronics / projects

author: Dunckx
author_rank: Contributor
timestamp: April 03, 2021, 04:55:41 pm
content: Hi Folks,For a while now I have been wanting to play with some picoamp leakage diodes and low noise JFETs and by sheer fluke (my usual favoured search technique) found a supplierhttps://shop.micross.com/shop-default.aspx.At the moment their online shop is being revamped and is not currently available, but if you email them an enquiry (address at the bottom left of the above webpage) you can buy stuff. In the UK the minimum order is £25, and UK carriage is £4-50, elsewhere in the world YMMV. They'll need you to complete an end use declaration to comply with US export regulations if you are outside the USA and presently the only available ordering system is for them to email you a quote in response to your email enquiry/order and then an invoice which must be paid by online bank transfer. Delivery time is typically two weeks as the parts come directly from the US manufacturer. Mine were packed in anti-static bags and these in an outer bag and all this within a padded bag.Bear in mind that Micross exists primarily to supply industry customers with gazillions of SMD chip resistors and capacitors by the trayload and the hobbyist market must be a tiny fraction of a percent of their business, so _please_ be nice to them!The parts which drew my attention were the small signal discretes from Linear Systems:http://www.linearsystems.com/and there's a blue button at the top right of the Linear Systems Homepage which says "download 2021 Data Book" and this lists their current production and gives datasheets for all.I was especially interested in the dual low noise FET LSK389A; this features in Jim Williams' "Quantifying Silence" application note AN-124. This is £7-23 ex-VAT at the time of typing and the picoamp diodes PAD1 TO72 £3-92 and dual picoamp diodes DPAD1 in TO78 £3-61. The low noise FET LSK170A in TO92 was £4-96. These are a small fraction of the cost of similar devices from the major retailers, compare especially the high end FETs at £20 to £40 each elsewhere and the FJH series of picoamp diodes which are typically twice the price of PAD1 and have a specified reverse leakage 10pA @ 15V, which is an order of magnitude bigger than (D)PAD1 1pA @ 20V. Whether you realise this leakage in practice I don't know and have no means of measuring it. I bet the package leakage between the leads across the surface of the insulator becomes significant at 20Tohms, especially in the presence of humidity. Sadly, the 2N4117A high impedance JFET is not presently available but there are other low leakage FETs, see data book. Many of these devices are available both in through-hole and surface mount, with metal cans available for some, so there should be something to please everybody.HTH

author: moffy
author_rank: Super Contributor
timestamp: April 04, 2021, 04:03:28 am
content: Nice

author: guymo
author_rank: Regular Contributor
timestamp: May 27, 2021, 06:23:56 pm
content: I guess that sometime in the few weeks since this post Micross changed their policy:my quote from them specified MOQ of 50 pieces per line, which took it out of my reach for sure.

author: floobydust
author_rank: Super Contributor
timestamp: May 27, 2021, 06:46:16 pm
content: Quote from: Dunckx on April 03, 2021, 04:55:41 pmLinear Systemsdo offer the 2N4117 as well as 2N4117A and improved LS4117.