My question is related to LMR61428 IC constant voltage output at low input voltage.

Sir I purchased  LMR61428 IC and LMR61428 Evaluation Module LMR61428XMMEVM , When I assembled the  LMR61428 IC  Circuit on PCB I am getting Vout ==3.3 times of Vinput.

But in Evaluation module I am getting  constant  5volt  output for input voltage range 2 to 4 volt. I have used circuit in assemble that have  mentioned in the datasheet of IC applications on page no.2 

Please tell me what changes i have to do in my PCB so that it work like LMR61428 Evaluation Module.

regards

Chandra