Diodes Incorporated ZMV933ATC

Overview

ZMV933ATC from Zetex Semiconductors is a 12 V hyperabrupt silicon varactor diode in SOT-23 package, designed for voltage-controlled frequency tuning in oscillator circuits. It delivers 42.0 pF capacitance at 1 V, 27.0 pF at 4 V, minimum Q of 150 at 50 MHz, reverse leakage ≤100 nA at 8 V, and octave tuning range (0–6 V). Used in TCXO/VCXO modules for mobile radio and wireless infrastructure.

For engineers reviewing the ZMV933ATC datasheet, ZMV933ATC pinout, ZMV933ATC application, or ZMV933ATC equivalent, key selection criteria include C-V linearity across 0–6 V, low phase-noise contribution via sub-100 nA IR, Q ≥150 at 50 MHz, SOT-23 thermal dissipation (330 mW), and compatibility with RF bias networks requiring common-cathode dual-diode layouts.

Technical Context

This hyperabrupt varactor uses graded doping to achieve near-linear 1/C² vs. voltage response, enabling stable frequency pulling in crystal oscillator loops. Its capacitance varies from 42.0 pF (1 V) to 12.0 pF (4 V), supporting octave tuning bandwidth with <±5% C tolerance across production lots.

The device operates with reverse bias only; forward current rating is 100 mA but not intended for conduction. Temperature coefficient of capacitance is +300 to +400 ppm/°C at 3 V, requiring compensation in high-stability TCXOs.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package: 3-terminal, single-anode/dual-cathode configuration (cathodes internally tied); standard JEDEC MO-203AA outline; body size 2.9 × 1.3 × 1.0 mm; 330 mW power rating at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZMV933ATA and ZC933TA, ZMV933ATC offers identical RF tuning performance but with SOT-23's higher power handling (330 mW vs. 250 mW) and broader industry-standard footprint support-critical for automated optical inspection and high-yield RF assembly.

Availability

ZMV933ATC is available at Aetrix Electronics and suitable for TCXO modules, wireless infrastructure filters, and mobile radio synthesizers requiring stable component supply with traceable lot history and full RoHS compliance.

Supply support for ZMV933ATC 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 focus on low-noise, high-Q, and precision-tolerance devices for timing and signal conditioning.

ZMV933ATC belongs to the ZMV93x hyperabrupt varactor family, engineered specifically for low-phase-noise oscillator tuning in telecom and industrial timing systems where C-V linearity and leakage stability are critical.

FAQ

What is the maximum recommended reverse bias voltage for continuous operation?

The absolute maximum reverse voltage is 12 V, but for reliable long-term operation in TCXO/VCXO applications, Zetex specifies 8 V as the maximum rated reverse bias. At 8 V, reverse leakage remains ≤100 nA, ensuring minimal frequency drift and phase noise degradation over temperature and time.

Does ZMV933ATC support dual-diode configurations?

ZMV933ATC is a single-anode/dual-cathode device in SOT-23, with cathodes internally shorted. It is functionally equivalent to a dual-common-cathode varactor, enabling balanced tuning in push-pull VCO topologies without external wiring-confirmed by Zetex Issue 7 schematic diagrams and pinout validation.

How does its Q factor compare to ZMV932ATC at 50 MHz?

ZMV933ATC has a minimum Q of 150 at 50 MHz, while ZMV932ATC specifies 200. This 50-point Q difference reflects the trade-off for extended capacitance range (42.0 pF vs. 17.0 pF at 1 V), making ZMV933ATC optimal for wide-pull oscillators where bandwidth outweighs ultimate phase-noise floor.

Is the SOT-23 pinout compatible with JEDEC standard MO-203AA?

Yes-ZMV933ATC conforms to JEDEC MO-203AA SOT-23 outline: Pin 1 (anode) at lead end, Pin 2 (cathode) center, Pin 3 (NC) opposite Pin 1. Mechanical dimensions (2.9 × 1.3 × 1.0 mm) and lead pitch (0.95 mm) match MO-203AA exactly, enabling use with standard pick-and-place and reflow tooling.