Varactor parametrics for VCO and filter tuning
The KVX3901A-23-0 is a single silicon tuning varactor in a non-hermetic plastic SOT-23-3 package, rated for 27 V peak reverse voltage and delivering 32 pF capacitance at 3 V bias. Its Q factor of 500 at 4 V and 50 MHz sets the resonator loss floor — a higher Q means the VCO tank or bandpass filter sees less resistive damping, which directly improves phase noise in an oscillator or insertion loss in a tunable filter. The 32 pF at 3 V is the nominal capacitance at a common bias point; the actual tuning range depends on how the capacitance changes as the reverse voltage swings from near-zero up to the 27 V peak reverse limit.
Temperature range and deployment envelope
Operating temperature spans -55°C to 125°C, covering the full military-grade band — this varactor suits avionics VCOs, satellite downconverters, and engine-bay RF modules that see both cold-soak and under-hood heat.
ROHS3 compliant, meaning it meets the current EU lead-free and halogen-free directive with no exemptions; no separate RoHS exemption certificate is needed for BOM compliance.