The Picor is fairly long/big and fairly expensive. It’s also a no-leads package, making it potentially difficult for novices to work with. I think that it won’t replace anything for now, but we should keep it in mind in case the need for such an extreme FET should come up. There is also the supply issue: AFAIK there is literally only this single FET which uses that package. If Picor stops making production runs of these things then any designs based on it are squashed. Frankly I haven’t even looked at it that closely, I suspect that the specifications probably preclude this use anyway. Yeah, take a look at the maximum Drain-to-Source voltage: it’s 5v. It wouldn’t be able to handle the spikes from single-cell DD use I think, and it certainly can’t handle 2s use.
Heh, good point RBD. For voltage monitoring on the Zener version (which I have not built) I’d think you’d want R1 to be in the 47k - 50k range. EDIT: (for 2s applications)
Thanks Tom E! Remember, this driver has only seen limited testing so far, so I don’t have all the answers.
Original Gangsta. It’s just a plain Jane XM-L. This one was previously in a SF dropin. I used two different HF meters to measure the tailcap current, several times. Current falls immediately, I’d estimate that less than 1s is spent over 9A. This is due to both the battery sagging and the “immediate turbo rampdown” firmware. This weekend I’ll get the dropin wrapped with foil and shoved medium-tightly into a host. I’ll run it for the full 30s+ and see whether it survives and how hot the host gets.
It’s unclear to me as well. The Vishay 70N02 datasheet is missing some critical graphs that I’d use for an easy comparison. It appears that the PSMN3R0-30YLD may be better for 1s applications. For Zener builds I think it’s pretty clear that performance should be identical for the two FETs.
I don’t have 14AWG; I guess I’ll have to try 12AWG and see? Really you should be able to install whatever you need, but I think that soldering to the triangular-ish center pad may be the most fiddly thing about assembling these.
I just yesterday ordered a dozen of these boards and the accompanying stencils to make life easier on me.
And I just a few moments ago opened a package with a proto board to assemble. So today it’s off to the races! Yippee! Even got a light to mod so it’s a good day.
Hell can be pretty sexy, so I don’t know about all that, but this is definitely a nice looking board! The one-sided design is VERY appealing!
Just from reading sales blurbs the LFPAK is supposed to bring DTP to the FET table and allow high power dissipation in a smaller package than the 70N02.
What’s interesting about that is that if you look at the datasheets it seems that the 70N02’s dissipation is actually package limited above 10v (Vgs) or so. The PSMN3R0-30YLD is may also be package limited at higher Vgs numbers, but there is also a more visible design limitation in the graphs. In the end maximum dissipation is actually much higher than what we need; the things which rein us in lay elsewhere in the spec.
Ahh - already submitted my DigiKey order this morn - my order was a mix because some parts like the 4.7K resistor I got plenty of, and need a lot more Tiny13A's. Should have parts for 12 of your designs. Now I have to order your boards
The Mouser cart is significantly cheaper, even after you figure in $1.77 higher shipping. Mouser’s prices are lower and I’ve swapped the expensive 10uF X7R bypass cap with a less expensive 10uF X5R bypass cap. In the end for QTY=10 you save nearly $5.
Very glad to see the availability of something that will
fit better in flashlights with retaining rings.
I just stumbled over a couple of hosts that came with retaining rings, on which I haven’t been able to use the drivers I have bought so far (not yet doing my own driver builds, likely not ever)
I’d appreciate mention of any drivers known for sale out there that satisfy this criterion, or anyone building these for sale.
the past 2 days I’ve been shopping around for parts to make BU_CK smaller now that I’ve got it up and running well, I looked up this FET cause I likes the sounds of it (the spec’s mentions) thinking it would work as a replacement for the D2PAK I’m using but the RDS (on) is pretty high on it, quite a bit higher than the AOD510.
I dont think it’ll work for my application but I wonder why that doesnt seem to be causing issues in this single cell / DD application, I had assumed the resistance was one of the huge things to watch in this application. I wonder what a better spec’d SO-8 FET would do on these things.
Note I’m not complaining, just thinking out loud. When we were first picking out FET’s when this whole DD method came about one of the largest factors (right behind the current rating) was the RDS (on), why back then was there so much fuss trying to find FET’s with super low resistance if in the end it apparently doesnt matter? Just seems to me 9A to an XM-L is pretty damn good. Would a FET with lower resistance do even more than that?
edit: Alex would you send me the .lbr part for that FET?