Modern UC384x equivalents

[ealex]

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)

[T3sl4co1l]

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/M1S0DbI
I update the part numbers from time to time, but not very exhaustively.  Suggestions welcome.

Tim

[ealex]

Thanks, LM3481 looks like it's the part I was looking for.
And LCSC seems to have some in stock

The 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.

[wasedadoc]

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".   

[ealex]

wasedadoc - i know ... i have several big projects stuck because they're using some highly specialized parts

I found some other interesting parts (that have more that 100 parts in stock at LCSC):

• FP5207XR-G1
  Vcc: 5 to 24V
  Vref: 1.2V
  VIsense: 0.1V
  Fsw: 100KHz to 1MHz
  Dmax: 90%
  https://datasheet.lcsc.com/lcsc/2109151030_Advanced-Analog-Technology-FP5207XR-G1_C2897211.pdf
  Notes: internal 6V LDO that's used by the gate driver, sparse datasheet, no info regarding slope compensation, etc
  
• LM3478
  Vcc: 2.97 to 40V
  Vref: 1.26V
  VIsense: 0.125 to 0.190V
  Fsw: 100KHz to 1MHz
  Dmax: 100%
  https://www.ti.com/lit/ds/snvs085x/snvs085x.pdf
  Notes: internal 7.2V LDO that's used by the gate driver
  
• LM3488
  Vcc: 2.97 to 40V
  Vref: 1.26V
  VIsense: 0.125 to 0.190V
  Fsw: 100KHz to 1MHz
  Dmax: 100%
  https://www.ti.com/lit/ds/symlink/lm3488.pdf
  Notes: seems identical to LM3478
  
• MAX668/MAX669
  Vcc: 3 to 28V (1.8 for MAX669)
  Vref: 1.250V
  VIsense: 100mV
  Fsw: 100KHz to 500KHz
  Dmax: 90%
  https://datasheets.maximintegrated.com/en/ds/MAX668-MAX669.pdf
  Notes: 5V LDO that's used by the gate driver,
  
• TPS40210/TPS40211
  Vcc: 4.5 to 52V
  Vref: 700 mV for TPS40210, 260 mV for TPS40211
  VIsense: 150mV
  Fsw: 35KHz to 1MHz
  Dmax: depends on Fsw - check Figure 2 in the datasheet
  https://www.ti.com/lit/ds/symlink/tps40210.pdf
  Notes: 8V LDO used by the gate driver, full duty cycle range under 100KHz
  

[T3sl4co1l]

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