RoadTest: SIMPLE SWITCHER®: LM46002PWP EVM by TI
Author: peteroakes
Creation date:
Evaluation Type: Evaluation Boards
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: Richtek EVB_RT7275GQW Evaluation Board
What were the biggest problems encountered?: Having a DC Load to test the Board with :)., a project for the summer :)
Detailed Review:
So right off the bat I would like to say this board definetly performed to exectations reaching over 90% efficient in some tests and exceeded the rated 2 Amps as well, I was able to push the board to 3Amps given the right input and still maintained low noise and ripple although it got pretty hot at those loads
All my testing was performed with the jumper installed to push the output to 5V (It would be 3.3V withut the jumper installed)
So performing this review I was always thinking of how it compared to the Richtek EVB_RT7275GQW Evaluation Board i reviewed in a previous road test and at the end of the day I think it was better due to the improved efficiency I was able to acheive and the increased input voltage range it was able to handle (60V vs 18 with the Richtek)
Here are the tqo bards side by side
Here is a comparison of the efficiency charts at various loads
The TI:
The Richtek
and for Load variations here is the TI (the current scale is 10* so it shows on he graph)
OK, so there is not much to actually show with this device, its all about how well it can keep its output stable through large swings of input volts or output load, based on the testing using a rudimentry DC Load it seems to perform very well and indeed exceeds the boards ratings. Though during this part of the test the board and particularly the Choke got quite hot so I would not feel confident running at this level for extended periods of time. Knowing it is able to handle over 50% more load intermittently though would be a comfort to anyone using this device in a critical project.
BOM (Bill of materials)
lets look at the schematics for the two
First up the TI
Now the Richtek
OK, I have not counted them but to me this looks like a tie, the TI is unsing a much larger inductor though at 10uH vs the Richtek 1.4uH
I have recorded several videos of the testing and will now include them as part of the review, In the videos I go through various scenarious testing output vs input voltage changes, Efficiency vs Load changes and finally a quick tour arround the various test pins on the board
part 1, the Input line regulation test
Next up, Load regulation tests
And finally the view of the various test pins on the board (The ones that where doing anything, this is while I was hammering the board with the load square wave
And here are some screen shots of the various test pins around the board
This is the response to a load change of about 2Amps, as you can see it recovered extreamly quickly and only dipped by about 200mV
This is the PG Pin while the above load profile keeps hammering away at the board, there is a lot of noise but I do not think all of it is comming from the board, I need to find what is generating this in my lab 
, the blue trace is the current switching in the load
This is the ground connection on the board while this load is being applied, see what I mean about the noise!
So the writeup looks short and sweet but there is a good few cups of coffee went into the videos so enjoy. I was very impressed with the performance of the TI switcher and this is not the first time, one of the very first requies I performed for Element 14 was on the TI Battery Booster Pack and it too had a couple of switching regulators, in this case, "buck boost" capapable and they too performed very well. Yes there where issues with the actual board but the chips where up to par in my book. TI yet again presents a niec roduce that can be applied in a variety of situations and if you check out their site, you can find plenty of information and even design tools allowing you to quickly design your board and figure out your BOM.
