Hello,
I am testing the SN6501 using a SN6501EVM-MULTI board. When I try any configuration with an output of 3V3, everything works as expected.
However, all configurations which output 5V, result in a very high level of ringing/ripple superimposed on the output voltage (whch is otherwise correct). The ringing is in some configurations as high as 2Vpp! The frequency of the 'ripple' varies but is usually around a few MHz. Looking at the board with a near field probe on a spectrum analyzer shows strong frequency spikes at the switching frequency (e.g. 360kHz for 3V3 in) and integer multiples of it all the way up to over 50MHz.
I've tried a variety of modifications such as output capacitors before and/or after the LDO, resistive loads, different power sources (incl. straight batteries). These things have a slight impact on the output, but are not significant with regards to the problem at hand.
Is this to be expected? Is there something wrong with my EVM? Or am I doing something wrong?
/Ross