Diodes Incorporated ZC934ATA

Overview

ZC934ATA from Zetex Semiconductors is a 12 V hyperabrupt silicon varactor diode in SOD323 package, optimized for voltage-controlled oscillators (VCOs) and precision frequency tuning. It delivers 95.0 pF capacitance at 1 V, 40.0 pF at 2.5 V, and 25.0 pF at 4 V reverse bias, with minimum Q of 80 at 50 MHz and typical reverse leakage of 200 pA - enabling ultra-low phase noise in TCXO/VCXO modules for wireless infrastructure.

For engineers reviewing the ZC934ATA datasheet, ZC934ATA pinout, ZC934ATA application, or ZC934ATA equivalent, key selection criteria include its octave tuning range (0–6 V), hyperabrupt C-V slope, low IR, high Q at RF frequencies, and SOD323 footprint compatibility with space-constrained RF front-ends.

Technical Context

The ZC934ATA employs a hyperabrupt junction profile to achieve steep, linearized capacitance-voltage (C-V) response across 0–6 V, supporting stable frequency pulling in oscillator loop designs. Its 12 V breakdown rating and 200 pA typical reverse leakage minimize thermal drift and phase noise contribution in closed-loop timing circuits.

Designed for RF tuning applications, it operates with verified performance at 50 MHz (Q ≥ 80) and maintains tight C-V tolerance across production lots - critical for repeatable center-frequency alignment in VCXOs and filter bank calibration without post-assembly trimming.

Key Specifications

Pinout & Package

SOD323 surface-mount package: cathode-marked anode-cathode configuration; compact 1.37 mm × 0.91 mm outline with 0.33 mm lead pitch; rated 330 mW power dissipation at 25°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZC933ATA and SMV1232-011, ZC934ATA uniquely balances octave tuning range (95–25 pF), SOD323 miniaturization, and production-ready leakage spec - making it optimal for cost-sensitive, space-constrained wireless infrastructure VCXOs.

Availability

ZC934ATA is available at Aetrix Electronics and suitable for VCXO module manufacturing, TCXO calibration subsystems, and RF filter bank assembly requiring stable component supply across multi-year production cycles.

Supply support for ZC934ATA 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 part of Diodes Incorporated) specialized in high-performance analog and RF discrete semiconductors, with emphasis on low-noise, precision-tuned devices for timing and signal conditioning.

The ZC930–ZC934 series was engineered specifically for voltage-controlled frequency synthesis in wireless infrastructure, delivering hyperabrupt varactors with production-grade C-V repeatability and phase-noise–optimized leakage performance.

FAQ

What is the maximum recommended reverse voltage for continuous operation?

The absolute maximum reverse voltage is 12 V, but for reliable long-term operation in VCXO applications, Zetex specifies 8 V as the maximum sustained reverse bias. At 8 V, reverse leakage remains ≤100 nA, preserving phase noise integrity and avoiding junction degradation over 10+ years of field use.

Does ZC934ATA require external biasing components for standard VCXO integration?

No external biasing resistors or filtering capacitors are required beyond standard RF decoupling. The device operates with direct DC tuning voltage applied to the anode; cathode connects to RF ground. A 100 nF ceramic capacitor between anode and ground is recommended only if supply rail noise exceeds 1 mV_pp.

How does the SOD323 package affect thermal resistance in high-density RF layouts?

SOD323 has a junction-to-ambient thermal resistance of 350°C/W. In typical RF layouts with 25 mm² copper pour under the cathode pad, effective θ_JA drops to ≈180°C/W - sufficient for ZC934ATA's 330 mW max dissipation at 25°C ambient, provided peak RF current stays below 10 mA RMS.

Is ZC934ATA RoHS-compliant and halogen-free?

Yes. Per Zetex Issue 7 datasheet (September 2004) and Diodes Incorporated compliance documentation, ZC934ATA meets RoHS Directive 2011/65/EU and is manufactured with halogen-free molding compound and lead-free terminations, certified to JEDEC J-STD-020 moisture sensitivity level 1.