A system in package ( SiP ) or system-in-a-package is a number of integrated circuits enclosed in a single module ( package ). The SiP performs all the functions of an electronic system , and is typically used within a mobile phone , digital music player , etc.  Dies containing integrated circuits can be stacked vertically on a substrate . They are internally connected by thin wires that are bound to the package. Alternatively, with a flip chip technology, solder bumps are used to join stacked chips together.
SiP dies can be stacked vertically or tiled horizontally , unlike slightly less dense multi-chip modules , which place dies horizontally on a carrier. SiP connects the dies with standard off-chip wire bonds or solder bumps, unlike slightly denser three-dimensional integrated circuits which connect stacked silicon dies with conductors running through the die.
Many different 3-D packaging techniques have been developed for stacking many more-or-less standard chip dies into a compact area. 
An example SiP can contain several chips-such as a specialized processor , DRAM , flash memory -combined with passive components- resistors and capacitors -all mounted on the same substrate. This means that a complete functional unit can be built in a multi-chip package, so that few external components need to be made to make it work. This is particularly valuable in space constrained environments like MP3 players and mobile phones as it reduces the complexity of the printed circuit boardand overall design. Despite its benefits, this technique decreases the yield of manufacturing since it is not a functional packaged integrated circuit.
SiP technology is primarily driven by market trends in wearables, mobile devices and the Internet of Things . As the IoT Becomes more of a reality and less of a vision, there is innovation going on at the system on a chip and SiP level n That MEMS sensors can be integrated was separate die and control the connectivity. 
SiP solutions may require multiple packaging technologies, such as flip chip , wire bonding , wafer-level packaging and more. 
- NANIUM, SA
- ASE Group
- ChipSiP Technology
- Cypress Semiconductors
- STATS ChipPAC Ltd
- Octavo Systems
- System on a chip
- Package on package
- Jump up^ By Pushkar Apte, William Bottoms, William Chen and George Scalise, IEEE Spectrum. “Advanced Chip Packaging Needs Smartphone Needs.” February 8, 2011. Retrieved July 31, 2015.
- Jump up^ By R. Wayne Johnson, Mark Strickland and David Gerke, NASA Electronic Parts and Packaging Program. “3-D Packaging: A Technology Review.” June 23, 2005. Retrieved July 31, 2015.
- Jump up^ By Ed Sperling, Semiconductor Engineering. “Why Packaging Matters.” November 19, 2015. Retrieved March 16, 2016.
- Jump up^ By Tech Search Chip Scale Review. “Major OSATs for Growth Opportunities in SiP.” May / June Issue. Retrieved June 22, 2016.