Part Number: TPS62745
Hello,
I am trying to design the tps62745 into a product and this supply (3.3V output version) will be supplying anywhere from 10mA to 10uA loads. I'm not sure exactly where in that window I will be yet. Most likely less than 1mA. This seemed like a great simple solution, but now that I have a test board with one of these up and running it is very noisy. I've attached a screenshot showing the output noise in orange (scope trace). This power supply is powering an op-amp and although it isn't extremely high precision it needs to be cleaner than what is shown in the scope capture. This power supply is shown in the second screenshot attached.
I believe this is connected just as it is shown in the data sheet example. There is no active circuitry on this board aside from this supply. The load is a BK precision 8601 active load. The input voltage is 8.2 volts.
Ch3 in scope capture = output of TPS supply with 10mA load for testing. I noticed that as I increase the load the switching speeds up and the peaks of this noise (sawtooth looking waveform) shrinks.
Is this the expected behavior of this supply? Should the inductor be increased to help smooth this out?
