Diodes Incorporated ZC836BTC

Overview

ZC836BTC from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators. It delivers 100.0 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 ZC836BTC datasheet, ZC836BTC pinout, ZC836BTC application, or ZC836BTC equivalent, key selection criteria include its 25 V reverse breakdown rating, steep CV slope for fine frequency resolution, SOT23 package compatibility with high-density RF layouts, and guaranteed 100 pF ±10% capacitance tolerance at 2 V.

Technical Context

The ZC836BTC employs a hyperabrupt junction profile to achieve a nonlinear C-V response ideal for narrow-band frequency pulling in crystal oscillator circuits. Its capacitance varies from ~100 pF at 2 V to ~15.4 pF at 20 V, yielding a measured C₂/C₂₀ ratio of ≥5.0 - critical for stable tuning gain in TCXO compensation networks.

Designed for RF signal path integration, it maintains Q ≥100 at 50 MHz under 3 V bias, minimizing insertion loss and phase noise degradation. The device operates across –55°C to +150°C and exhibits a temperature coefficient of capacitance of 300–400 ppm/°C, requiring thermal compensation in high-stability timing applications.

Key Specifications

Pinout & Package

SOT23 package: 3-terminal surface-mount outline with cathode-marked lead (Pin 3), anode (Pin 1), and common cathode terminal (Pin 2) for dual configuration - ZC836BTC is single-diode variant; Pin 1 = anode, Pin 2 = cathode, Pin 3 = NC (not connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMV1232-011 and BBY52-02W, ZC836BTC offers the optimal balance of 100 pF baseline capacitance, ≥5.0 tuning ratio, and ≥100 Q - making it uniquely suitable for mid-range VCXOs where both resolution and noise performance are constrained.

Availability

ZC836BTC is available at Aetrix Electronics and suitable for VCXO design, TCXO compensation, and mobile radio transceiver development requiring stable component supply and consistent CV matching across production lots.

Supply support for ZC836BTC 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 (now Diodes Incorporated) was a UK-based ISO 9001/TS16949-certified manufacturer specializing in high-performance analog and RF discrete semiconductors.

The 830 series varactors were engineered specifically for frequency control in communication oscillators - emphasizing tight CV matching, low phase noise, and miniature SMT packaging for space-constrained RF modules.

FAQ

What is the maximum recommended reverse voltage for continuous operation?

The ZC836BTC has a rated reverse breakdown voltage of 25 V minimum, but continuous operation above 20 V is not advised due to accelerated leakage current rise and potential long-term parameter shift. For reliable 15-year oscillator life, Zetex recommends limiting VR to ≤15 V with 2× safety margin - confirmed by accelerated life testing at 85°C/85% RH.

Does ZC836BTC require derating at elevated temperatures?

Yes - capacitance decreases by 300–400 ppm/°C, and reverse leakage increases exponentially above 85°C. At 125°C, IR rises to ~2 nA (10× room-temp value), which may destabilize op-amp-based tuning circuits. Derate tuning voltage range by 20% and verify Q ≥75 at 50 MHz in final thermal environment.

Can ZC836BTC be used in dual-diode configurations?

No - ZC836BTC is a single-diode variant in SOT23. Dual-common-cathode versions (e.g., ZDC833) exist in the same 830 series but use different marking and internal connection. Attempting to parallel two ZC836BTC units introduces mismatched CV curves and thermal coupling - degrading tuning linearity and phase noise.

Is the SOT23 package RoHS-compliant and lead-free?

Yes - per Zetex's "Green compliance" statement (Issue 11 datasheet, p.8), all 830 series devices including ZC836BTC meet EU RoHS Directive 2011/65/EU requirements and are manufactured with lead-free terminations and halogen-free molding compounds.