Diodes Incorporated ZMV835ATC

Overview

ZMV835ATC from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators. It delivers 68.0 pF nominal capacitance at 2 V, 5.0–6.5 capacitance ratio (C₂/C₂₀), ≥100 Q at 50 MHz, and ultra-low reverse leakage (200 pA typ.), enabling low-phase-noise VCXO/TCXO designs in wireless infrastructure and mobile radio front-ends.

For engineers reviewing the ZMV835ATC datasheet, ZMV835ATC pinout, ZMV835ATC application, or ZMV835ATC equivalent, key selection criteria include its 25 V reverse breakdown rating, −55°C to +150°C operating range, SOT23 package compatibility, and verified CV slope linearity for stable VCO gain control in RF synthesizers.

Technical Context

ZMV835ATC operates as a voltage-dependent capacitor with hyperabrupt doping profile, yielding steep, predictable C–V slope essential for linear frequency modulation in oscillator feedback loops. Its capacitance varies from ~74.8 pF at 2 V to ~11.5 pF at 20 V, supporting wide tuning bandwidths while maintaining phase noise below −150 dBc/Hz at 10 kHz offset.

The device exhibits tight process-controlled CV tolerance (±5% for 835A grade), temperature coefficient of capacitance between 300–400 ppm/°C, and reverse leakage limited to 20 nA max at 20 V - critical for minimizing oscillator drift and long-term frequency stability in temperature-varying environments.

Key Specifications

Pinout & Package

SOT23 package: 3-terminal surface-mount plastic case with cathode-marked lead (Pin 3). Standard JEDEC MO-178 footprint; 2.9 mm × 1.3 mm × 1.0 mm body size; 1.9 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZMV835ATC, SMV2023-011LF trades tuning range for superior Q and voltage margin, while BBY58-02W offers higher baseline capacitance in a smaller package but sacrifices CV linearity and breakdown rating - selection depends on whether VCO gain flatness, phase noise floor, or board area is the dominant constraint.

Availability

ZMV835ATC is available at Aetrix Electronics and suitable for VCXO design, RF synthesizer development, and wireless transceiver filtering requiring stable component supply with guaranteed long-term availability and RoHS-compliant manufacturing.

Supply support for ZMV835ATC 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

Zetex Semiconductors plc was a UK-based ISO 9001 and TS16949-certified manufacturer specializing in high-performance analog and RF discrete semiconductors before its acquisition by Diodes Incorporated in 2008.

ZMV835ATC belongs to the 830-series hyperabrupt varactor family, engineered specifically for low-phase-noise frequency control in telecom oscillators and tunable RF filters - emphasizing CV precision, thermal stability, and high-Q performance over broad voltage ranges.

FAQ

What is the maximum recommended reverse voltage for continuous operation?

The absolute maximum reverse voltage is 25 V, but Zetex specifies derated operation at ≤20 V for long-term reliability. At 20 V, reverse leakage remains ≤20 nA, and capacitance retains ≥11.5 pF - ensuring stable tuning behavior without junction degradation or accelerated aging in production-grade oscillators.

Does ZMV835ATC have a specified cathode marking convention on the SOT23 package?

Yes: the cathode is marked by a visible bar or notch adjacent to Pin 3 on the top surface of the SOT23 package. Per Zetex package drawings, Pin 3 is the designated cathode terminal, and Pin 2 is internally bonded to the same cathode structure - confirming it is a single-diode, not dual-cathode, configuration despite earlier series documentation ambiguity.

How does the 300–400 ppm/°C temperature coefficient impact TCXO design?

This coefficient means capacitance changes by 0.03–0.04% per °C, directly translating to frequency drift in crystal oscillators. In TCXO designs, it necessitates complementary thermistor networks or DAC-based compensation algorithms calibrated to counteract this slope - Zetex's tight CV tolerance across temperature simplifies the required compensation resolution by ±10%.

Is ZMV835ATC suitable for use in 5G FR1 front-end tunable matching networks?

No - while its Q ≥100 at 50 MHz is excellent for sub-6 GHz oscillator tanks, its Q drops significantly above 1 GHz due to series resistance and package parasitics. For 5G FR1 (600 MHz–3.8 GHz) impedance tuning, devices like Skyworks SMS7621 or MACOM MA4PBL020 must be used instead, as they maintain Q >60 up to 4 GHz with optimized SOD-323 or SC-79 packaging.