In this paper, a novel soft switching passive snubber cell for family of isolated/non-isolated pulse width modulation DC-DC converter is proposed. In this proposed converter, the switch is turned on with zero current switching (ZCS) and is turned off with zero voltage switching (ZVS). Besides, the main diode is turned on and off with ZVS and ZCS, respectively. In addition, the reverse recovery losses of main diode are minimized. The auxiliary diodes in the snubber cell are operated with soft switching. The proposed converter has a simple structure, low cost and ease of application. The detailed theoretical analysis of new converter is made, and a 200-W laboratory prototype is implemented. The theoretical analysis is confirmed with the experimental results. Finally, the proposed passive snubber cell is applied to family of other isolated/non-isolated DC-DC converter in order to provide soft switching.