SiP (System-in-Package) solution realizes an extremely small sized system which is suitable for mixed-signal mobile applications. However, integration of digital and RF dies with a number of interconnections between them within limited area can cause noise coupling from digital circuits to RF circuits. In this paper, a fully operating T-DMB (Terrestrial Digital Multimedia Broadcasting) system is implemented in a form of a 3-D (three-dimensional) SiP by stacking dies, on which a series of design methodologies to improve the noise isolation level between digital and RF signals, is applied. As a result, the size of system is reduced to 10mm x 10mm, which is the smallest size for full T-DMB system with multimedia, and RF sensitivity is enhanced by 17dB and 45dB for band-3(173-240MHz) and L-band (1.452~1.492GHz), respectively.