Microchip Technology KV3902

Overview

KV3902 from Microsemi is a hyperabrupt junction RF varactor diode in DO-34 hermetic glass package, designed for voltage-controlled tuning in UHF VCOs and frequency modulators. It delivers C_T = 22.5–27.5 pF at 3 V, capacitance ratio C(3V)/C(25V) = 2.9–3.5, Q ≥ 115 at 50 MHz, V_R = 30 V, and operates from –55 °C to +150 °C.

For engineers reviewing the KV3902 datasheet, KV3902 pinout, KV3902 application, or KV3902 equivalent, key selection criteria include its 25 pF nominal capacitance at 3 V, 3.2 typical capacitance ratio, 115 minimum Q at 50 MHz, low-inductance DO-34 package, and suitability for linear-frequency VCXO/TCXO tuning across 3–8 V bias range.

Technical Context

The KV3902 uses computer-controlled grown-junction epitaxy to achieve exceptional parameter reproducibility and ultrahigh Q in a 30 V-rated hyperabrupt structure. Its hyperabrupt doping profile enables straight-line frequency tuning over 3–8 V reverse bias, supporting octave LC tank tuning up to 500 MHz.

Capacitance swing (22.5–27.5 pF @ 3 V, 6.8–8.9 pF @ 25 V) and low series resistance yield Q ≥ 115 @ 50 MHz, critical for minimizing VCO phase noise. The diode is rated for continuous operation up to +150 °C with MIL-spec SiO₂ passivation and RoHS-compliant gold terminations.

Key Specifications

Pinout & Package

DO-34 hermetic glass package with axial leads and green cathode stripe marking. Cathode is identified by colored stripe; anode is unmarked lead.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar varactor diode applications.

Compared with KV3902, MAVR-000120-1411 offers SMT compatibility at the cost of Q and temperature range, while SMV1232-011 improves Q but sacrifices hermeticity and extended temperature capability - KV3902 remains optimal for high-reliability UHF tuning where stability and ruggedness are critical.

Availability

KV3902 is available at Aetrix Electronics and suitable for UHF VCOs, frequency modulators, VCXOs, and TCXOs requiring stable component supply across industrial, aerospace, and test equipment programs.

Supply support for KV3902 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microsemi (now part of Microchip Technology) is a semiconductor company specializing in high-reliability analog, RF, and timing solutions for aerospace, defense, and industrial markets.

The KV3201–KV3902 series was engineered specifically for UHF hyperabrupt tuning applications demanding high Q, wide C-swing, and hermetic reliability - targeting VCOs, modulators, and precision oscillator compensation networks.

FAQ

What is the nominal capacitance of KV3902 at 3 V reverse bias?

The KV3902 has a typical capacitance of 25 pF at 3 V reverse bias, with a guaranteed range of 22.5–27.5 pF per the manufacturer's datasheet. This value is measured at 1 MHz and defines the primary tuning point for LC tank design in VCO and filter applications. The KV3902's tight distribution supports predictable frequency alignment without post-production trimming.

Does KV3902 support linear frequency tuning, and over what voltage range?

Yes, KV3902 supports straight-line frequency tuning over a 3–8 V reverse bias range due to its hyperabrupt junction profile. This behavior is explicitly confirmed in the datasheet for VCXO/TCXO and frequency modulator use cases. Within this range, KV3902 delivers monotonic, low-distortion frequency deviation - critical for analog FM and precision oscillator pulling.

What is the maximum reverse voltage rating for KV3902?

KV3902 has a maximum working reverse voltage (V_R) of 30 V, verified per absolute maximum ratings. Its breakdown voltage (V_BR) is ≥30 V at 10 µA, ensuring robust operation with margin in 25 V-tuned circuits. Exceeding 30 V risks irreversible junction damage, and operation above 25 V significantly reduces usable capacitance swing.

Is KV3902 suitable for high-temperature environments?

Yes, KV3902 is rated for continuous operation from –55 °C to +150 °C, with no derating required up to +150 °C. Its hermetic DO-34 package and MIL-spec SiO₂ passivation ensure parameter stability and long-term reliability in extended-temperature industrial, aerospace, and downhole applications - a key differentiator versus plastic-packaged alternatives.

How does KV3902 compare to KV3901 in terms of capacitance and tuning range?

KV3902 offers 22.5–27.5 pF at 3 V and a C(3V)/C(25V) ratio of 2.9–3.5, whereas KV3901 provides 26–32 pF at 3 V and a higher ratio of 4.5–6.0. Thus, KV3902 targets mid-range UHF tuning with improved linearity, while KV3901 suits wider-range or higher-C applications. Both share identical V_R, Q, and package - KV3902 is not a drop-in replacement for KV3901 due to capacitance mismatch.