Diodes Incorporated ZC835BTA

Overview

ZC835BTA from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators, featuring 64.6–71.4 pF capacitance at 2 V, 5.0–6.5 capacitance ratio (C₂/C₂₀), and <20 nA reverse leakage at 20 V. It operates in SOT23 surface-mount package and delivers high Q (>100 at 50 MHz) and low phase noise for VCXO/TCXO reference circuits.

For engineers reviewing the ZC835BTA datasheet, ZC835BTA pinout, ZC835BTA application, or ZC835BTA equivalent, key selection criteria include its hyperabrupt CV slope, tight capacitance tolerance (±5% typical), low IR, and compatibility with miniature RF tuning networks in wireless infrastructure and mobile radio front-ends.

Technical Context

ZC835BTA employs a silicon hyperabrupt junction structure to achieve steep, linearized C–V response ideal for stable frequency pulling in oscillator tanks. Its capacitance varies from ~68 pF at 2 V to ~10.4 pF at 20 V, enabling wide tuning range with minimal voltage sensitivity drift.

The device exhibits temperature coefficient of capacitance of +300 to +400 ppm/°C and maintains Q >100 at 50 MHz under 3 V bias-critical for minimizing phase noise in crystal oscillator loops where varactor-induced jitter dominates close-in spectral purity.

Key Specifications

Pinout & Package

Supplied in SOT23 package (JEDEC TO-236AB), 3-terminal configuration with anode, cathode, and case (cathode-connected tab). Standard marking "J6B" identifies ZC835BTA on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMV2023-011LF and BBY58-02W, ZC835BTA offers superior capacitance tolerance control and lower leakage-making it preferred for high-stability TCXOs-while retaining SOT23 compatibility that BBY58-02W shares but SMV2023-011LF does not.

Availability

ZC835BTA is available at Aetrix Electronics and suitable for VCXO reference tuning, TCXO temperature compensation, and mobile radio VCO applications requiring stable component supply, consistent CV matching, and RoHS-compliant SMT assembly.

Supply support for ZC835BTA 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.

ZC835BTA belongs to the 830-series hyperabrupt varactor family, engineered specifically for low-phase-noise frequency control in precision timing and wireless transceiver applications where CV linearity and repeatability are critical.

FAQ

What is the maximum recommended reverse voltage for continuous operation?

The absolute maximum reverse voltage is 25 V per the datasheet, but continuous operation above 20 V is not advised due to accelerated aging from field-enhanced leakage. For long-term reliability in TCXO applications, bias should be limited to 15 V with 2 V headroom, ensuring IR remains below 5 nA and tempco stays within ±10% of nominal.

How does the SOT23 package affect RF performance compared to SOD-323?

ZC835BTA's SOT23 package provides lower thermal resistance (≈200 K/W) than SOD-323, improving power handling in high-Q tank circuits. Its larger pad area also reduces parasitic inductance (<0.3 nH vs. 0.5 nH), preserving Q above 50 MHz-critical for 100+ MHz VCXO designs where SOD-323 introduces measurable resonance shift.

Can ZC835BTA replace ZC835ATA in existing designs?

Yes-ZC835BTA and ZC835ATA share identical electrical specs and SOT23 packaging; only the capacitance bin differs (B-bin: 64.6–71.4 pF vs. A-bin: 61.2–74.8 pF). The tighter B-bin tolerance reduces frequency calibration time in production, and no layout or bias network changes are required for substitution.

Is ZC835BTA suitable for automotive-grade temperature ranges?

ZC835BTA is rated for –55°C to +150°C operating temperature, meeting AEC-Q200 stress test requirements for passive components. Its tempco stability and low IR ensure usable CV characteristics across this range, though system-level validation is required for ASIL-B timing functions per ISO 26262.