Printed circuit board assembly and assembling method thereof

A printed circuit board assembly comprising:

• a printed circuit board comprising at least one first through hole;
• at least one electronic device comprising a first surface, a second surface and at least one pin, wherein the first surface and the second surface are opposite to each other, and the pin passes through the first through hole of the printed circuit board and is inserted on the printed circuit board;
• a holder secured to the printed circuit board and disposed between the printed circuit board and the electronic device, wherein the holder comprises a supporting surface and at least one opening, the supporting surface sustains the first surface of the electronic device and the at least one opening is disposed on the supporting surface to receive the at least one pin of the electronic device to pass therethrough, wherein the holder is configured to provide a gap between the supporting surface and the printed circuit board;
• and
• a heat-dissipation device comprising a heat-dissipation surface thermally coupled with the second surface of the electronic device.