LM5164: Help selecting buck converter

Hello,

 I need help selecting buck converter to replace LM5164. This part was great but in my app the noise created by frequency modulation/bursts at low load are just not acceptable.

Design specs: Vin, 28V +/-5V, Vout 3V - 26V - must be contiously adjusted on the fly - not fixed, Iout  500mA max. Typipical work 10-50mA.

To my understanding for PWM mode at ligh loads converter should be able to divert some current to gnd on its own when required. And in general which topology would be best for such use in wide out0put range : Voltage Regulation or Current Regulation or COT?

Thanks