Miscellaneous RF ICs are devices that perform electronic functions on RF signals. There are a great variety of types of parts in this category optimized to fulfill a need of a specific application. Such application areas include: broadcast television, wireless communications, Wi-Fi, Bluetooth, RFID and cellular.

RF ICs are capable of performing modulation or demodulation and the up/down conversion  that adhere to standards compliance for receiving and transmitting of RF signals for interoperability. They usually integrate functions like: filtering, amplification, mixing, signal generation and automatic gain control (AGC). Some modems (for example analog FFSK) may incorporate sophisticated math functions like auto-correlation.

Important specifications that receiver RF ICs are required to meet include receiver selectivity and sensitivity. Sensitivity is a function associated with the noise figure (NF) of the amplifications stages and the losses in the filtering networks. Selectivity is a function of the ability of a receiver to separate the information signal from interferers that may be on adjacent channels. Different standards require different sensitivity or selectivity tradeoffs. Intermodulation specifications are also important. Third order intermodulation (IP3) specifies the 1dB compression point of the receiver and is an indicator of a receiver’s linearity and distortion caused by harmonic mixing products.

RF ICs that transmit RF signals must adhere to regulatory standards. They must stay within the applicable standard’s transmitter power levels and frequency envelop. This prevents the RF IC from interfering with other equipment. Transmitted signals must comply with the applicable wireless protocol standard to enable interoperability and prevent interference with other equipment. This requires compliance with physical and data link layer rules for characteristics such as: synchronization, timing, framing and packet formats. RF ICs that transmit must comply with standards pertaining to conducted spurious emissions and electromagnetic interference (EMI) regulations. This places additional filtering and shielding requirements on the device.

Devices intended for general use might have variants specifically qualified to meet automotive fault, EMI and temperature approval standards. Other examples of RF ICs include broadband wireless devices that support antenna diversity or multiple antenna switching. Antenna switches may also include built-in memory to store last selection and blanking circuits for the signal during switching and at low signal levels. There are also devices like RF Immobilizer chips (Initiator ICs) that have integrated RFID communications. They are used to prevent theft by allowing selective enabling of the ignition system.