Diodes Incorporated ZC833ATC

Overview

ZC833ATC from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators, with nominal capacitance of 33.0 pF at 2 V, capacitance ratio C₂/C₂₀ = 5.0–6.5, Q ≥ 200 at 50 MHz, and reverse leakage ≤ 200 pA. It operates up to 25 V reverse bias and is packaged in SOT23 for RF filtering and VCXO/TCXO calibration circuits.

For engineers reviewing the ZC833ATC datasheet, ZC833ATC pinout, ZC833ATC application, or ZC833ATC equivalent, key selection criteria include its hyperabrupt CV slope (300–400 ppm/°C tempco), low phase-noise contribution in oscillator tanks, tight ±5% capacitance tolerance (ZC833A grade), and SOT23-compatible footprint for high-density RF layout.

Technical Context

The ZC833ATC implements a hyperabrupt junction profile to deliver steep, linearized voltage-to-capacitance response-critical for stable tuning in VCXOs where small control-voltage changes must yield predictable frequency shifts. Its 25 V breakdown rating and <20 nA IR at 20 V support robust operation in temperature-compensated oscillator loops.

Designed for RF impedance matching and tank circuit tuning, it exhibits a measured Q ≥ 200 at 50 MHz and 3 V bias, enabling low-loss resonance in 100–500 MHz VCO designs. The device's 300–400 ppm/°C capacitance temperature coefficient is tightly specified to minimize drift-induced frequency error in TCXO compensation networks.

Key Specifications

Pinout & Package

Package: SOT23 - 3-lead surface-mount package with cathode-marked lead (Pin 3), standard footprint compatible with automated placement and reflow.

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, ZC833ATC offers superior balance of tuning ratio, Q, and 25 V rating-making it optimal for industrial-grade VCXOs requiring both wide pull range and low phase noise at elevated bias.

Availability

ZC833ATC is available at Aetrix Electronics and suitable for VCXO calibration, TCXO compensation, and RF filter tuning requiring stable component supply, consistent CV matching, and RoHS-compliant SMT assembly.

Supply support for ZC833ATC 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 analog and RF discrete semiconductors before its acquisition by Diodes Incorporated in 2008.

The 830 series varactors were engineered specifically for precision frequency control in telecom timing modules, emphasizing hyperabrupt CV linearity, ultra-low leakage, and thermal stability in oscillator tank circuits.

FAQ

What is the maximum reverse voltage rating for ZC833ATC?

The ZC833ATC has an absolute maximum reverse breakdown voltage of 25 V at I_R = 10 µA, verified per Zetex Issue 11 datasheet. Operation above 20 V is not recommended for long-term reliability, as leakage increases nonlinearly beyond that point while Q degrades.

Does ZC833ATC have a specified capacitance tolerance?

Yes-the ZC833A grade (denoted by 'A' in part number) guarantees capacitance of 29.7–36.3 pF at 2 V, representing ±5% tolerance around the nominal 33.0 pF value. This is confirmed in the "Electrical characteristics" table on page 3 of the January 2007 datasheet.

Is ZC833ATC suitable for use in TCXO compensation networks?

Yes-its specified temperature coefficient of 300–400 ppm/°C at 3 V and 1 MHz aligns closely with AT-cut quartz crystal drift profiles. Combined with low leakage and high Q, it enables accurate analog compensation in commercial-grade TCXOs operating from –40°C to +85°C.

Which package variant does ZC833ATC use?

ZC833ATC uses the SOT23 package, as confirmed by order code suffix 'TA' (7-inch reel) and package outline drawings on page 5 of the datasheet. Pin configuration follows standard SOT23 anode-cathode-anode layout with cathode marked on Pin 2/3 edge.