A system on module (SOM) is a board that integrates the main elements of a processing subsystem and plugs or solders into a carrier card/board. Elements include: microprocessor, non-volatile flash memory, volatile memory technologies such as RAM and DRAM, clock management and power management (PMIC). The SOM will typically contain peripheral functionality integrated into the microprocessor system on chip (SOC). Application specific functionality such as I/O connections are implemented on the carrier board.

Advantages of SOMs include rapid, lower risk hardware development, lower system cost and the potential for processor upgrade. Rapid hardware development is achieved because of the processor board’s immediate availability. Risk is mitigated on design and manufacturing errors on the high density element of the prototype hardware. Lower system cost can be realized by reducing PCB cost in the overall system through separation of the higher technology PCB and manufacturing element from the peripheral system. Rather than double-sided placement on a large board with a high layer count due to the processing subsystems requirements, the carrier board can be lower technology and cost. Processor upgrades can be achieved by replacing one SOM with the next generation SOM with a compatible interface and form factor.