LT3094 -ve LDO equiv to LT3045 - Page 1
Forum section: electronics / general

author: alanambrose
author_rank: Frequent Contributor
timestamp: August 28, 2018, 09:16:08 am
content: Hi, FYI I just noticed this comment:https://ez.analog.com/thread/109212-can-the-lt3045-be-used-to-regulate-both-a-positive-and-negative-voltage-rail#comment-361010... but can't see other info atm.Alan{edit - I meant 3045 rather than 3095}

author: TiN
author_rank: Super Contributor
timestamp: August 28, 2018, 09:20:56 am
content: I've used LT3092, it's nearly same as 3042/45.

author: coppercone2
author_rank: Super Contributor
timestamp: August 28, 2018, 11:42:47 am
content: Can you link a picture so we don't need to register to AD website (ridiclous)I assume you are asking about making some kind of negative LDO that has a ridiculously low noise floor and great RF PSRR ?I don't see a LT3094 chip?I noticed in general there are no good manufactured equivalents of chips in the same ball park, maybe because of PNP stage?You said 94 now 95 and 45 can you fix everything I am very confused.

author: Echo88
author_rank: Frequent Contributor
timestamp: August 28, 2018, 11:51:39 am
content: Seems they changed the Analog.com-Forum to log in only this day.Anyway:https://www.mouser.com/pdfdocs/ADI_LDO_General_Presentation_2018Apr1.pdfThe LT3094 seems to have the same specs as its positive LT3045-brother.

author: coppercone2
author_rank: Super Contributor
timestamp: August 28, 2018, 07:57:11 pm
content: Quote from: Echo88 on August 28, 2018, 11:51:39 amI am excited for that part. The order of magnitude difference was very irritating IMO. ~0.8 vs 18 !!!

author: alanambrose
author_rank: Frequent Contributor
timestamp: August 30, 2018, 10:03:48 am
content: Apologies for the slightly cryptic and erroneous initial title.>>> I assume you are asking about making some kind of negative LDO that has a ridiculously low noise floor and great RF PSRR ?Yes I think this is of general interest here.>>> Anyway:https://www.mouser.com/pdfdocs/ADI_LDO_General_Presentation_2018Apr1.pdfThe LT3094 seems to have the same specs as its positive LT3045-brother.Wow, that's a nice presentation.Amazing to see the favourable comparison with Li-ion noise; the absolutely critical layout; and the magnetic field analysis.Alan

author: Echo88
author_rank: Frequent Contributor
timestamp: September 10, 2018, 02:30:08 pm
content: https://media.digikey.com/pdf/Data%20Sheets/Analog%20Devices%20PDFs/LT3094_Rev0_9-5-18.pdf

author: splin
author_rank: Frequent Contributor
timestamp: September 10, 2018, 10:46:07 pm
content: The 3042 and 3045 are pretty expensive, so how much might an external pass device, to increase output, compromise the noise performance?What is likely to be the biggest factor behind the big improvement over previous regulators? Reference noise perhaps?

author: Echo88
author_rank: Frequent Contributor
timestamp: September 19, 2018, 10:22:10 pm
content: Update: Digikey has the LT3094 in stock, while Analog.com still doesnt list it as a part.

author: branadic
author_rank: Super Contributor
timestamp: September 20, 2018, 08:03:15 am
content: Quote from: splin on September 10, 2018, 10:46:07 pmQuoteinstead of a voltage reference.-branadic-

author: MiDi
author_rank: Frequent Contributor
timestamp: September 24, 2018, 11:58:04 am
content: Quote from: Echo88 on August 28, 2018, 11:51:39 amLuckily this seems not to be an April's fool

author: MiDi
author_rank: Frequent Contributor
timestamp: October 18, 2018, 05:16:51 am
content: https://youtu.be/_U-KD5tHUuE

author: TiN
author_rank: Super Contributor
timestamp: October 18, 2018, 05:26:23 am
content: I got few some weeks ago from Digikey, but they still sit in ESD bag

author: MiDi
author_rank: Frequent Contributor
timestamp: October 18, 2018, 08:11:52 am
content: If you are curious whats inside the christmas cookie box: take a look atAN159

author: Gerhard_dk4xp
author_rank: Frequent Contributor
timestamp: October 21, 2018, 05:44:14 pm
content: Quote from: splin on September 10, 2018, 10:46:07 pmIt is not much worse.<https://www.flickr.com/photos/137684711@N07/29452163806/in/album-72157662535945536/>Circuit is like the one in the data sheet. Measurement was quick & dirty without thesecond alu coffin.<https://www.flickr.com/photos/137684711@N07/29197476530/in/album-72157662535945536/>To the left / right are measurements of other devices that might be interesting.The stronger than 1/f increase of the noise at low frequencies is my preamplfier, the input capacitorwas too small for an effective bias network short. -3dB is not everything. :-)That has been healed with a wet slug tantalum; I intend to repeat the measurement campaign withthe new version of the amplifier.0 dB == 1 nV/rt Hz.The reference is a current source; that is much easier to decouple than a low impedancevoltage source. Don't overdo it with the output capacitor or you'll get noise peaks.regards,Gerhard