Diodes Incorporated ZMV831ATA

Overview

ZMV831ATA from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators and RF filters. It delivers 15.0 pF nominal capacitance at 2 V, 4.5–6.0 capacitance ratio (C₂/C₂₀), ≥300 Q at 50 MHz, and ultra-low reverse leakage (typ. 200 pA), enabling low-phase-noise VCXO/TCXO designs in wireless infrastructure and mobile radio front-ends.

For engineers reviewing the ZMV831ATA datasheet, ZMV831ATA pinout, ZMV831ATA application, or ZMV831ATA equivalent, key selection criteria include its hyperabrupt CV slope for steep tuning response, SOT23 package compatibility with high-density RF layouts, 25 V reverse breakdown rating, and guaranteed 13.5–16.5 pF capacitance tolerance at 2 V - critical for stable oscillator pullability and filter tracking accuracy.

Technical Context

ZMV831ATA employs a hyperabrupt junction profile to achieve a steep, linearized C–V curve ideal for wide-range frequency control. Its capacitance varies from ~16.5 pF at 2 V to ~3.0 pF at 20 V, yielding a minimum C₂/C₂₀ ratio of 4.5 under 1 MHz test conditions.

The device operates with reverse bias only and exhibits temperature coefficient of capacitance between +300 and +400 ppm/°C. Its 25 V reverse breakdown voltage and ≤20 nA leakage at 20 V ensure robust performance in battery-powered and temperature-variable RF modules.

Key Specifications

Pinout & Package

ZMV831ATA is housed in an industry-standard SOT23 surface-mount package (JEDEC TO-236AB), measuring 2.67–3.05 mm × 1.20–1.40 mm × 0.95 mm height, with gull-wing leads for reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZMV831BTA and ZC831ATA, ZMV831ATA offers the broadest capacitance tolerance window for cost-sensitive VCXO designs where post-production calibration is acceptable, while retaining full electrical equivalence in Q, leakage, and tuning linearity.

Availability

ZMV831ATA is available at Aetrix Electronics and suitable for VCXO frequency control, RF bandpass filter tuning, and mobile radio transmitter applications requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for ZMV831ATA 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 designer and manufacturer of high-performance analog and RF semiconductors, acquired by Diodes Incorporated in 2008.

ZMV831ATA belongs to the 830-series hyperabrupt varactor family, engineered specifically for low-phase-noise frequency synthesis in wireless communications infrastructure, where precise C–V linearity and high Q are mandatory for spectral compliance.

FAQ

What is the maximum recommended reverse voltage for continuous operation of ZMV831ATA?

ZMV831ATA has a rated reverse breakdown voltage of 25 V, but continuous operation above 20 V is not recommended due to accelerated leakage current rise and potential long-term parameter drift. For reliable 10+ year field life in VCXOs, Zetex specifies 20 V as the absolute maximum DC reverse bias under all operating conditions.

Does ZMV831ATA require external series resistance in the tuning line?

Yes - a 10–100 kΩ series resistor is recommended between the tuning voltage source and the anode to limit transient current during power-up and prevent junction damage from ESD or supply overshoot. This resistor also damps parasitic resonance with PCB trace inductance, improving VCO stability.

Can ZMV831ATA be used in place of ZMV830ATA in an existing design?

ZMV831ATA provides 15.0 pF nominal capacitance versus ZMV830ATA's 10.0 pF, resulting in ~50% lower tuning sensitivity (MHz/V). Substitution requires recalculating loop gain and phase margin in the oscillator; it is not a drop-in replacement unless the design has ≥30% excess pullability margin.

Is ZMV831ATA RoHS-compliant and lead-free?

Yes - ZMV831ATA conforms to the EU RoHS Directive 2011/65/EU and is manufactured with lead-free terminations and halogen-free molding compound. The SOT23 package uses matte tin plating over nickel barrier, qualified to JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1).