Diodes - Variable Capacitance, commonly known as Varicaps or Varactors, are a specialized type of diode designed primarily to act as a voltage-controlled capacitor. Unlike regular capacitors, whose capacitance is fixed, the capacitance of a Varicap can be altered by changing the voltage across it. This unique feature makes them very useful in tuning and frequency control applications. They are key components in voltage-controlled oscillators (VCOs), phase-locked loops (PLLs), and in filter circuits where the electrical tuning of the circuit is required. The main characteristics of Varicaps include their ability to offer a wide range of capacitance values, high linearity, and low tuning voltages, which are essential for precise and flexible circuit tuning.
Varactors find their main uses in communication equipment like radios, televisions and cell phones, where they help in fine-tuning frequencies and maintaining stable signal processing. They are also commonly used in RF design and are vital for applications that require the dynamic adjustment of the circuit's capacitance based on the applied voltage. Notable manufacturers of Diodes - Variable Capacitance (Varicaps, Varactors) include STMicroelectronics, Infineon Technologies, NXP Semiconductors, and Vishay Intertechnology, among others.