Diodes Incorporated ZMDC832BTA

Overview

ZMDC832BTA from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators and RF filters. It delivers 22.0 pF nominal capacitance at 2 V, 5.0–6.5 capacitance ratio (C₂/C₂₀), ≥200 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 ZMDC832BTA datasheet, ZMDC832BTA pinout, ZMDC832BTA application, or ZMDC832BTA equivalent, key selection criteria include its SOT23 package compatibility, hyperabrupt CV slope for steep tuning response, 25 V reverse breakdown rating, and verified performance in temperature-stable oscillator loops requiring <0.4 ppm/°C capacitance drift.

Technical Context

ZMDC832BTA is a single-die, common-cathode hyperabrupt junction varactor engineered for high-slope dC/dV response across 2–20 V reverse bias. Its doping profile yields a controlled capacitance vs. voltage curve with ±5% tolerance on C₂ and C₂₀ values, supporting stable loop gain in PLL-based synthesizers.

The device operates within –55°C to +150°C, exhibits 300–400 ppm/°C temperature coefficient of capacitance at 3 V, and maintains <20 nA reverse leakage up to 20 V - critical for minimizing oscillator phase noise floor and long-term frequency drift in battery-powered radios.

Key Specifications

Pinout & Package

Supplied in SOT23 surface-mount package (JEDEC TO-236AB), with cathode marked by a bar on lead 3. Thermal resistance θ_JA = 378°C/W; max power dissipation = 330 mW at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZMDC832BTA, SMV2023-011LF offers superior Q for jitter-critical clock sources but sacrifices tuning range, while BBY52-02W provides higher base capacitance at lower cost and voltage rating - making it suitable for non-telecom consumer-grade VCOs where thermal stability is less demanding.

Availability

ZMDC832BTA is available at Aetrix Electronics and suitable for VCXO calibration, TCXO temperature compensation, and mobile radio VCO design requiring stable component supply, tight CV matching, and low-phase-noise performance.

Supply support for ZMDC832BTA 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/TS16949-certified manufacturer specializing in high-performance discrete semiconductors before its acquisition by Diodes Incorporated in 2008.

ZMDC832BTA belongs to the 830-series hyperabrupt varactor family, designed specifically for precision frequency control in telecom-grade oscillators and RF filters where CV slope linearity and low leakage are mandatory.

FAQ

What is the maximum recommended reverse voltage for continuous operation?

The absolute maximum reverse voltage is 25 V, but Zetex specifies 20 V as the maximum operating reverse voltage for reliable long-term performance. Operating above 20 V increases reverse leakage exponentially and accelerates junction degradation, especially above 85°C ambient. For TCXO applications, bias is typically limited to 12 V to maintain CV linearity and minimize tempco drift.

Does ZMDC832BTA have a dual-anode configuration?

Yes - ZMDC832BTA is a dual-anode, common-cathode varactor in SOT23 package (pins 1 and 2 are anodes, pin 3 is cathode). This configuration supports balanced tuning in differential VCO architectures and enables redundancy or extended tuning range when both anodes are used with independent bias paths.

How does its hyperabrupt junction differ from standard abrupt varactors?

ZMDC832BTA's hyperabrupt doping profile yields a capacitance–voltage relationship where C ∝ V^−γ with γ ≈ 1.8–2.2, versus γ ≈ 0.5 for abrupt junctions. This results in ~3× steeper dC/dV slope near zero bias - essential for achieving high KVCO in compact VCO designs without sacrificing linearity over the usable tuning range.

Is this part RoHS compliant and lead-free?

Yes - ZMDC832BTA is RoHS-compliant and lead-free, consistent with Zetex's green compliance program documented in Issue 11 (January 2007). The SOT23 package uses matte tin (Sn) termination finish, and all materials meet EU Directive 2011/65/EU requirements, including exemption 7a for lead in high-melting-temperature solder alloys.