The programmable capacitors are active integrated circuits offering a variable capacitance value that can be easily programmed through a digital protocol.
Mainly used for calibrating frequency devices like crystal oscillators, VCXOs, OCXOs and/or any other wireless front-end –reducing the errors and tolerances-, these capacitors are able to modify their value in small steps (down to fentofarads), providing an accurate tuning for the radiofrequency devices.
The possibility of storing the calibrated values in a non-volatile memory makes this solution a suitable replacement of any analog varactor, making easier the operational tuning through a digital programming, as well as reducing the bill of materials since no biasing circuitry is needed.
Different Cmax/Cmin and different capacitor step - Different operating frequencies (up to 3GHz)
Different type of non-volatile memory
Different Series Programming Interface (I2C, SPI, proprietary)
Shunt (one terminal to ground) or series (differential capacitor) configurations
Different voltage range for different designs
Possibility for programming several devices sharing the bus for PCB space saving.
The programmable capacitors can be easily qualified with the test evaluation boards. Different reference designs, like automated 50 Ohm matching network or 2.4GHz antenna tuning are also available to validate the programmable capacitors.