X60008 Voltage Reference IC - Page 1
Forum section: electronics / general

author: floobydust
author_rank: Super Contributor
timestamp: August 24, 2017, 07:18:31 pm
content: Whatever happened to theX60008?It didn't incorporate a heater, accuracy ±500?V (±0.01%) initial, max. 1ppm/°C, aging 10ppm/1khrs and usesXFET.It looked pretty good, I have some in aMalone Electronicslow cost voltage reference.Nut's n Volts magazine build 9/2007That semiconductor merger & acquisition crap comes along. Xicor originally designed it 2004, then Intersil buys Xicor for $0.52 Billion. 2017 Renesas buys Intersil for $3 Billion (but Maxim wanted to buy them) and the IC's are gone now, Intersil has discontinued their highest performing references, odd politics.Maxim has a voltage reference lineupMAX6335, 6241, 6250that is similar in cost and spec, but I'm not a fan of their parts.I can't see anything to replace it for the price point ~$7. Any suggestions?Xicor/Intersil Voltage Reference Application and Design Note AN177

author: Andreas
author_rank: Super Contributor
timestamp: August 24, 2017, 08:58:37 pm
content: Quote from: floobydust on August 24, 2017, 07:18:31 pmHello,sorry but: its not XFET but FGA-technology (storage of the output voltage in a kind of EEPROM cell).I cannot speak for the X60008 since it was out of production when I started to examine 5V references.Instead I used the ISL21009BFB850.there are 3 issues which I have with the ISL21009BFB850- switch off hysteresiswhen running for several days and then you measure the steady state output voltage.switch off for some secondsswitch on againthe ISL21009BFB850 starts some 100uV (around 200-300uV) below the steady state output voltageit needs some days until the steady state output voltage is reached again.attached a around 10 hours plot with 1 minute switchoff at the beginning.would be interesting if this "feature" is also available on the X60008.- radiation sensitivityI have never seen a application note on any other reference to convince customers that a reference is enough radiation hardened.- sensitivity to capacitive loads.you need a boucherot cirquit to stabilize the output when loading with several nF capacity.I would go for a AD586 or LT1236 for a really good device.with best regardsAndreas

author: floobydust
author_rank: Super Contributor
timestamp: August 27, 2017, 09:58:24 pm
content: Thanks. I mixed that up, it's FGA (floating-gate analog) technology I was not familiar with."...Typically the trapped charge on the floating gate can remain without loss for greater than 10 years."Hmmm a bit skeptical on the long term stability.NASA took the X60008, ISL60002 down to cryogenic -195°C temperatures.Measured drift was 3.25 ppm/°CI'm sure radiation would knock out those stored electrons, odd NASA would even consider the technology for space exploration.

author: montemcguire
author_rank: Regular Contributor
timestamp: September 10, 2017, 02:37:43 am
content: Intersil has an application note that addresses this issue:http://www.intersil.com/content/dam/Intersil/documents/an15/an1533.pdfYes, it is sort of creepy, but they say that a relatively thin zinc shield can filter out the X rays that cause problems.An odd possibility: the FGA voltage could be trimmed by exposure to X rays post-assembly. Probably only trimmed in one direction, but heck, it seems possible. :-)