Diodes Incorporated FMMV2101TA

Overview

FMMV2101TA from ON Semiconductor is a silicon planar variable capacitance diode (varactor) in SOT-23 package, rated for 30 V reverse voltage, 6.8 pF nominal capacitance at 4 V/1 MHz, and 2.5–3.3 tuning ratio (C₂/C₃₀). It delivers 450 typical Q-factor at 4 V/50 MHz and operates from –55 °C to +150 °C, used in VCOs and RF tuning circuits for UHF TV tuners and wireless transceivers.

For engineers reviewing the FMMV2101TA datasheet, FMMV2101TA pinout, FMMV2101TA application, or FMMV2101TA equivalent, key selection criteria include capacitance vs. voltage curve linearity, Q-factor at operating frequency, temperature coefficient (280–400 ppm/°C), SOT-23 thermal dissipation capability, and tuning ratio stability across temperature.

Technical Context

This varactor diode exploits voltage-dependent depletion-layer capacitance in a planar silicon junction. Its C–V response is optimized for linear tuning in oscillator and filter applications, with low series inductance (3.0 nH at 250 MHz) and minimal case capacitance (0.15 pF).

Designed for analog RF signal path tuning, it supports bias voltages from 0 to 25 V reverse, exhibits low leakage (20 nA at 25 V), and maintains stable capacitance characteristics over its full operating temperature range (–55 to +150 °C).

Key Specifications

Pinout & Package

Package: SOT-23 (3-pin, surface-mount plastic). Standard pinout per JEDEC TO-236AB: Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Not connected (NC) - confirmed via ON Semiconductor FMMV2101TA datasheet Issue 3 (Jan 1996) and device marking "6R".

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMV2023-011LF and BBY52-02W, FMMV2101TA offers optimal balance of mid-range capacitance (6.8 pF), high Q (450), and wide tuning ratio (2.5–3.3) in SOT-23 - making it preferred for UHF VCOs requiring both spectral purity and broad frequency agility.

Availability

FMMV2101TA is available at Aetrix Electronics and suitable for UHF TV tuners, ISM band transceivers, FM radio local oscillators, and automotive keyless entry systems requiring stable component supply across extended temperature ranges.

Supply support for FMMV2101TA 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and communications markets.

FMMV2101TA belongs to ON Semiconductor's legacy RF varactor diode product line, engineered specifically for high-Q, temperature-stable voltage-controlled tuning in broadcast and wireless infrastructure applications.

FAQ

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

The absolute maximum reverse voltage is 30 V, but for reliable long-term operation, ON Semiconductor specifies 25 V as the maximum continuous reverse bias under all conditions including temperature extremes and transient spikes. Exceeding 25 V risks accelerated degradation of junction integrity and capacitance drift.

How does the 0.15 pF case capacitance affect matching network design?

The 0.15 pF case capacitance appears in parallel with the active junction capacitance and must be subtracted from measured total capacitance to obtain true diode C_j. In high-Q VCO designs, this parasitic term directly impacts calculated inductor values and can shift resonance by up to 1.5% if unaccounted for in layout simulation.

Is FMMV2101TA suitable for use in DC-coupled tuning circuits?

No - FMMV2101TA must operate under reverse bias only. Forward conduction degrades junction characteristics and causes irreversible capacitance hysteresis. All tuning circuits must ensure cathode voltage remains ≥0.7 V above anode voltage at all times, typically using blocking capacitors or dedicated bias tees.

Does the "6R" marking correspond to a specific capacitance bin?

Yes - "6R" denotes the FMMV2101 variant with nominal 6.8 pF capacitance at 4 V/1 MHz and guaranteed tuning ratio of 2.5–3.3. This marking aligns with ON Semiconductor's binning specification in Issue 3 (January 1996) and is laser-etched on the top surface of the SOT-23 package.