Diodes Incorporated ZC829BTC

Overview

ZC829BTC from Zetex Semiconductors is a silicon hyperabrupt varactor diode optimized for voltage-controlled frequency tuning in precision oscillators and RF filters. It delivers 8.2 pF nominal capacitance at 2 V, 4.3–5.8 capacitance ratio (C₂/C₂₀), ≥250 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 ZC829BTC datasheet, ZC829BTC pinout, ZC829BTC application, or ZC829BTC equivalent, key selection criteria include its hyperabrupt CV slope, SOT23 package compatibility with high-density RF layouts, guaranteed C₂/C₂₀ tuning ratio, and verified low IR performance critical for oscillator phase noise floor.

Technical Context

The ZC829BTC implements a hyperabrupt junction profile to achieve steep, linearized voltage-to-capacitance response-essential for stable frequency pulling in VCXOs. Its 25 V reverse breakdown rating and −55°C to +150°C operating range support robust operation in temperature-varying RF modules.

Designed for 1 MHz–50 MHz tuning bands, it maintains ≥250 Q at 50 MHz and exhibits tight ±5% capacitance tolerance (ZC829B grade) with 300–400 ppm/°C temperature coefficient-enabling predictable drift compensation in TCXO compensation networks.

Key Specifications

Pinout & Package

Supplied in SOT23 surface-mount package (3.05 × 1.40 × 1.10 mm), with cathode marked by molded notch and laser top-side marking "J9B".

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZC829BTC, MAVR-000120-1411 trades Q for extended tuning range-ideal for non-critical IF filters-while SMV2023-011 offers superior tolerance at reduced capacitance, better suited to high-frequency VCOs than crystal-based timing circuits.

Availability

ZC829BTC is available at Aetrix Electronics and suitable for VCXO design, TCXO compensation, and wireless transceiver VCO tuning requiring stable component supply with traceable lot history and RoHS-compliant packaging.

Supply support for ZC829BTC 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 frequency control in precision timing and wireless infrastructure-emphasizing hyperabrupt CV linearity, low phase noise, and miniature SMT reliability.

FAQ

What is the maximum reverse voltage rating for ZC829BTC?

ZC829BTC has a guaranteed minimum reverse breakdown voltage of 25 V at I_R = 10 µA. Operation above 20 V is not recommended for long-term reliability, as leakage current rises exponentially beyond this point per the datasheet's absolute maximum ratings table.

Does ZC829BTC require derating at elevated temperatures?

Yes-capacitance decreases by 300–400 ppm/°C, and Q degrades above 85°C. The device remains functional up to +150°C, but designers must model C(T) drift in TCXO compensation algorithms and limit power dissipation to maintain junction temperature below 125°C.

Is ZC829BTC compatible with lead-free reflow profiles?

Yes-ZC829BTC's SOT23 package meets JEDEC J-STD-020D moisture sensitivity level 1 and supports peak reflow temperatures up to 260°C for 10 seconds. No pre-bake is required, and the device passes thermal cycling tests from −55°C to +150°C per MIL-STD-750 Method 1017.

How does ZC829BTC's hyperabrupt profile differ from standard abrupt varactors?

ZC829BTC uses a graded doping profile that produces a near-linear C–V relationship over 2–20 V, whereas abrupt varactors exhibit quadratic C–V curves. This yields flatter tuning gain (MHz/V) and reduced harmonic distortion in VCO control loops-critical for EVM-sensitive LTE and 5G transmitters.