Just got mine this evening. Time to blast some chiptune and begin testing! Did anyone want me to test for anything specific? I've got access to fancy university oscilloscopes, function generators, infrared thermometers and such, so I intend to test its response time at various input/output voltages, and frequencies while varying the load at various frequencies, verify the info on the datasheet holds true, as well as push it to its lower, then upper operational limits, all while monitoring the temperature of the components and certain areas of the pcb. Maybe even swap out some of the smds to see how fussy it is. I'll also investigate the purpose of the holes. Offhand, my guess would be that, while they do connect ground on either side of the board they are mainly for cooling purposes/to cope with 3A, otherwise the 2 ground leads would suffice. Let me know if your interested in testing anything else, and I'll do my best =D
I would expect it should be ok, 18V @166mA is not the dissipation in the regulator, it is the energy transfer to the load AKA 3W and is an average
internally the FET switches will be either full on or full of, fully on the resistance will be measured in the milli-ohms so the power loss there will be minimal
A boost regulator is far worse and the ones I have used still barely get warm to the touch
It will be interesting to see the road-test on this one. still 18V at 166mA is still quite high based on the datasheet. but whether I am interpreting the datasheet correctly is yet to be determined.
I don't have the time to do it myself so I will watch this with interest.
It appears to be a basic BUCK regulator albeit with a very large inductor for the size of the control IC. As such there very efficient and of course do not generate any significant heat, even with 18V in and 1V out at 3A, that's a 3W load but still only 3W in from the source 18V too so only 166mA would be drawn from the supply (Less inefficiencies). The regulator (Switching circuit) will barely break a sweat
Hi Andy, it appears to be a FET switching so drop-out voltages are not the main issue.
I found the datasheet to be extremely limited though, i wanted to locate the maximum power rating at the higher voltages and could not locate anything other than 2.6W and 1.67W. But this is conflicting as this equates to less than 3A even at 1.05V. It is possible the massive number of holes could be heat sink stitching to peak offer better thermal conductivity but overall the spec sheet seem to only be catered for 1.05V.
The RT7275GQW looks like a useful chip. I'm afraid I don't have to test equipment necessary to do a decent road test on it though.
I can't seem to find what the dropout voltage is, i.e. if I wanted 5v on the output what is the minimum voltage I could place on the input?
The description says that there is no internal clock but there is a 700kHz Switching Frequency, can you clarify what that means?
I'm fasinated by all the holes in the PCB, is that simply so that there is enough copper connecting the PCB layers to cope with the 3A load or is there another reason for it?