Modern UC384x equivalents - Page 1
Forum section: electronics / beginners

author: ealex
author_rank: Frequent Contributor
timestamp: November 30, 2022, 10:41:53 am
content: Hello,I've been trying to find some "modern" equivalent for the UC384x series.I'm mostly looking for lower working voltage - 5v for example, and, maybe lower current limit voltage (compared to the 1V used in 384x series)User T3sl4co1l made a list in an old post - I remember seeing it, but I can't find it now.Do you know any IC's that can fit the description ? Even if they're available only from LCSC or Aliexpress, as long I can translate the datasheet to English.Best regards, Alex(sorry for the edit - I've accidentally clicked on submit)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 30, 2022, 11:26:55 am
content: LM3481 is probably what you're looking for.Casually in defense of 384x's high current limit voltage, you can at least pull it up, from VREF statically, or as part of slope compensation (follower from RtCt) -- but only so far before tolerances dominate, say for 300 or 200mV at the shunt. A more sensitive input in the first place would indeed be nicer.Nice to have internal slope comp, too. Keeps things simpler and more useful.The meme(s) is here:https://imgur.com/a/M1S0DbII update the part numbers from time to time, but not very exhaustively. Suggestions welcome.Tim

author: ealex
author_rank: Frequent Contributor
timestamp: December 01, 2022, 06:15:28 am
content: Thanks, LM3481 looks like it's the part I was looking for.And LCSC seems to have some in stockThe 86% duty cycle limit is strange, but I can work around that - make a small fly-back instead of a simple boost.Also, NCV3063 looks interesting - I'll take a closer look at it's datasheet.I'll take a look over LCSC - maybe I can find something that has better availability (LM3481 will be back in 2024 at mouser ... ) and add it to this post.

author: wasedadoc
author_rank: Super Contributor
timestamp: December 01, 2022, 01:40:48 pm
content: Those far off dates like 2024 are meaningless. They are there because the database software doesn't permit the date "We haven't a clue".

author: ealex
author_rank: Frequent Contributor
timestamp: December 02, 2022, 10:08:51 am
content: wasedadoc - i know ... i have several big projects stuck because they're using some highly specialized partsI found some other interesting parts (that have more that 100 parts in stock at LCSC):FP5207XR-G1Vcc: 5 to 24VVref: 1.2VVIsense: 0.1VFsw: 100KHz to 1MHzDmax: 90%https://datasheet.lcsc.com/lcsc/2109151030_Advanced-Analog-Technology-FP5207XR-G1_C2897211.pdfNotes: internal 6V LDO that's used by the gate driver, sparse datasheet, no info regarding slope compensation, etcLM3478Vcc: 2.97 to 40VVref: 1.26VVIsense: 0.125 to 0.190VFsw: 100KHz to 1MHzDmax: 100%https://www.ti.com/lit/ds/snvs085x/snvs085x.pdfNotes: internal 7.2V LDO that's used by the gate driverLM3488Vcc: 2.97 to 40VVref: 1.26VVIsense: 0.125 to 0.190VFsw: 100KHz to 1MHzDmax: 100%https://www.ti.com/lit/ds/symlink/lm3488.pdfNotes: seems identical to LM3478MAX668/MAX669Vcc: 3 to 28V (1.8 for MAX669)Vref: 1.250VVIsense: 100mVFsw: 100KHz to 500KHzDmax: 90%https://datasheets.maximintegrated.com/en/ds/MAX668-MAX669.pdfNotes: 5V LDO that's used by the gate driver,TPS40210/TPS40211Vcc: 4.5 to 52VVref: 700 mV for TPS40210, 260 mV for TPS40211VIsense: 150mVFsw: 35KHz to 1MHzDmax: depends on Fsw - check Figure 2 in the datasheethttps://www.ti.com/lit/ds/symlink/tps40210.pdfNotes: 8V LDO used by the gate driver, full duty cycle range under 100KHz

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 02, 2022, 01:00:16 pm
content: Strike TPS40210 -- its fault threshold is within the normal range of error amp output, so it just faults out all the time under heavy load. I don't know how or why it exists...Tim