We're getting an output sine wave on the LDO of the TPS65721. It's not consistently present - sometimes when it's under battery power or powered by a wall charger, it's not present. We've tried reducing the impedance of the resistor dividers to stabilize the output, but that did not work.
The ripple on the LDO line is 5-10mV, but it's continuous and the amplifiers on the board are amplifying it instead of rejecting it. I can mess around with the components on the DC/DC converter, but it seems that perhaps changing the LDO components might get better results (perhaps the 22pF feedback capacitor).
Anyone else have any issues like these? Thanks very much!