Diodes Incorporated ZC932TC

Overview

ZC932TC from Zetex Semiconductors is a 12 V hyperabrupt silicon varactor diode in SOT23 package, designed for voltage-controlled frequency tuning in precision oscillators. It delivers 17.0 pF capacitance at 1 V, 8.5 pF at 2.5 V, and 5.5 pF at 4 V reverse bias, with minimum Q of 200 at 50 MHz and typical reverse leakage of 200 pA - enabling low-phase-noise VCXO/TCXO designs for mobile radio and wireless infrastructure.

For engineers reviewing the ZC932TC datasheet, ZC932TC pinout, ZC932TC application, or ZC932TC equivalent, key selection criteria include its hyperabrupt C-V slope (octave tuning from 0–6 V), tight CV tolerance, low IR, high Q at RF frequencies, and SOT23-compatible footprint for space-constrained timing modules.

Technical Context

This varactor operates as a voltage-dependent capacitor in resonant tank circuits, where applied reverse bias modulates junction capacitance via hyperabrupt doping profile. Its C-V curve enables wide, linear-in-octave tuning range - critical for stable frequency pulling in VCXOs and TCXOs.

Designed for RF signal path integration, it exhibits low phase noise due to sub-100 nA leakage at 8 V and high Q (>200 at 50 MHz), minimizing energy loss and oscillator close-in noise. The SOT23 package supports reflow-compatible assembly in compact timing modules.

Key Specifications

Pinout & Package

SOT23 package: 3-pin surface-mount plastic case with gull-wing leads; standardized footprint compatible with automated placement and reflow soldering. Cathode marked by band; anode and cathode terminals defined per JEDEC TO-236AB outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZC932TC, ZC931TA offers superior Q for noise-critical VCOs but narrower tuning span, while ZC933TA sacrifices Q for broader low-frequency coverage - making ZC932TC the balanced choice for 100–200 MHz VCXOs demanding both stability and pullability.

Availability

ZC932TC is available at Aetrix Electronics and suitable for VCXO design, TCXO manufacturing, and wireless infrastructure filter tuning requiring stable component supply, consistent C-V matching, and traceable lot-level qualification.

Supply support for ZC932TC 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 discrete semiconductors, particularly RF and precision analog devices, with global design and support centers in UK, Germany, US, and Hong Kong.

The ZC932TC belongs to Zetex's hyperabrupt varactor series engineered specifically for low-phase-noise frequency control in telecom timing modules, mobile radios, and programmable filters - emphasizing CV linearity, leakage control, and package reliability.

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 rated reverse bias. Operating continuously at 12 V risks accelerated junction degradation and increased leakage, especially above 70°C ambient.

Does ZC932TC require derating at elevated temperatures?

Yes - reverse leakage increases exponentially with temperature, doubling approximately every 10°C above 25°C. At 85°C, leakage may reach 10 nA, impacting phase noise; designers must verify bias network stability and consider thermal shielding in high-density timing modules.

Is the SOT23 pinout compatible with standard pick-and-place equipment?

Yes - ZC932TC uses JEDEC-standard SOT23-3 (TO-236AB) footprint with 0.95 mm lead pitch and 1.3 mm body width. Its gull-wing leads and coplanarity ≤0.1 mm meet IPC-7351 Class B requirements for automated assembly without modification.

How does the temperature coefficient of capacitance affect TCXO design?

With a specified 300–400 ppm/°C tempco at 3 V, ZC932TC introduces measurable center-frequency drift if uncorrected. In TCXO designs, this tempco must be actively compensated using thermistor networks or digital calibration to achieve sub-ppm stability over −40 to +85°C.