So I’m in the process of converting my drivers to use the DAC instead of PWM, there was two reasons I was on the fence about the DAC :
- the lower resolution of 8bits, which would make the bottom of the ramp quite coarse and decrease the dimming range, even with 2 sense resistors (HDR) the minimum for a 5A 6V driver would be 77uA 6V, my goal has always been at least 100uA 3V (ZL H600 II) so that’s not enough, but if Gchart succeeds to implement dynamic VREF then there will be enough resolution.
- the main point about using the DAC is to not have to use the LDO and a bunch of passives that comes with it and PWM (input C for LDO, VBATT divider, PWM RC filter), but I need a constant voltage to drive the HDR FET that switches between the two sense resistors, since the Rdson of this FET is part of the total Rsense it has to remain constant through the whole battery range (4.2 to 2.8V). Except that was with the previous FET, the new one I use has a very flat RDSON/VGS curve according to the datasheet, so I measured it to be sure :
Only about +0.25mΩ from 4.2 to 2.8V, which for example on a total Rsense of 8mΩ means only –3% output current at 2.8V vs 4.2V, which is… completely fine!
Additionally the DAC is faster than filtered PWM, which is good for fast strobe modes, it produces no ripple, and shouldn’t make a flash when ramping up, so no delay needed on HDR FET turn on.
Conclusion : let’s remove the LDO and 5 passives.
Thanks to the lower component count the BCK18_HDR (18mm clearance) driver can be one sided.
You should see how I’m equipped 
I think many modders here have better equipments than me.
For reflowing I do it on a ”hotplate” which is just a small sheet of copper heated by my soldering iron. For the second side or for rework I preheat the board on the hotplate (with a spacer) and heat the top of the board with an infrared heating tool I made from a car cigar lighter…
For applying the paste, because I prototype a lot buying stencils each time would cost quite bit, so I use one only for the T1616, I do the rest manually with this dispenser which main advantage is to dispense precisely with one hand, same precision can be achieve with two hands and a 1ml syringe with 25G tip. But once I’ll have more final versions I’ll use stencils because it is so much faster and easier.
And then a small 10x loupe for inspection, but that’s it mostly, a bit primitive but it works.
About parts, well I built an inventory because I prototype, but once you have a BOM that’s not a problem.
Though I understand that people would prefer to buy already made drivers, I looked very briefly at PCB assembly services before but I haven’t done a simulation or something like that, what I remember seeing here is a GXB172 driver group buy that never went through due to not enough quantity to be viable. One problem is also the many different sizes.
About the Dx series, I skimmed through it when you posted it on Gchart’s thread, but I don’t know what is really good for us there, the bigger DB ones have internal Op Amps, but with 8mV max V offset they are not suited for our application. Still only one DAC output so we can’t use it for dual channel drivers, but it’s 10bit so thats better than 1 series, DU has native USB but unfortunately sacrifices the DAC for it.
