The LV25300M is a tuner system that supports the SDRS300 (SANYO car audio DSP) that allows the creation of standard tuner modules. Various setting changes can be performed with the software of the control microcontroller according to the intended application. Small tuner modules can be developed with a smaller number of parts compared to conventional tuners and at a lower total cost. Moreover, the LV25300M comes with an antenna switching diversity function that switches two antennas in response to various electric field changes while the vehicle is running, a malfunction prevention circuit that operates through antenna switching frequency detection, and a weak electric field detection, and antenna fixing circuit that uses S meter voltage, making stable reception possible.