onsemi MMT05A230T3G

Overview

MMT05A230T3 from onsemi is a bidirectional thyristor surge protective device (TSPD) designed for secondary overvoltage protection in telecom line interfaces. It features 265–280 V breakover voltage, 50 A 10 × 1000 µs surge current rating, 150–340 mA holding current, and SMA surface-mount package. It operates across −40 °C to +125 °C and shorts fail-safe under overstress-used in customer-premises telecom equipment per Telcordia GR-1089, ITU K.20/K.21, and IEC 950.

For engineers reviewing the MMT05A230T3 datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional clamping voltage stability, dv/dt immunity (2000 V/µs), low off-state leakage (<2.0 µA at 50 V), fail-safe shorting behavior, and compliance with telecom surge standards.

Technical Context

The MMT05A230T3 functions as a crowbar-type protector triggered by voltage breakover-not avalanche or zener conduction. Its bidirectional symmetry enables identical forward/reverse surge response without polarity sensitivity, and its turn-off relies solely on current decay below holding threshold (IH = 150–340 mA).

It delivers stable clamping with minimal voltage variation across transient amplitude or slew rate due to thyristor physics, and exhibits no wear-out mechanisms typical of gas discharge tubes or MOVs. Thermal limits include TJ(max) = +175 °C during conduction and TL = 260 °C for soldering.

Key Specifications

Pinout & Package

SMA package (Case 403D-02), surface-mount, non-polarized bidirectional device with two terminals: MT1 and MT2. No anode/cathode distinction-identical electrical behavior in either direction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar thyristor surge protection applications.

Compared with SM2T270AY and P6SMB270A, the MMT05A230T3 uniquely combines bidirectional crowbar action, fail-safe shorting, and telecom-grade regulatory compliance-making it the preferred choice for secondary protection where reliability and standards adherence are mandatory.

Availability

MMT05A230T3 is available at Aetrix Electronics and suitable for DSL line interface protection, VoIP gateway design, ISDN terminal equipment, and remote-powered telecom devices requiring stable component supply and long-term lifecycle support.

Supply support for MMT05A230T3 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensor, and logic solutions for automotive, industrial, cloud computing, and communications markets.

The MMT05A230T3 belongs to onsemi's Thyristor Surge Protector (TSPD) family-engineered specifically for secondary-level overvoltage protection in telecom infrastructure, emphasizing fail-safe operation, regulatory compliance, and long-term reliability in harsh environments.

FAQ

What is the primary function of the MMT05A230T3 in a telecom circuit?

The MMT05A230T3 serves as a bidirectional crowbar-type surge protector that triggers at 265–280 V to short-circuit transient overvoltages-diverting surge current away from sensitive downstream components like codecs or SLICs. Its fail-safe shorting behavior ensures continued protection even after overstress, distinguishing it from non-latching protectors. The MMT05A230T3 is rated for 50 A 10 × 1000 µs surges and meets Telcordia GR-1089 and ITU K.20/K.21 standards.

Does the MMT05A230T3 require external bias or control circuitry to operate?

No, the MMT05A230T3 is a passive, self-triggering device requiring no external bias, control signals, or drive circuitry. It conducts automatically when voltage across MT1–MT2 exceeds its breakover threshold (V_BO), and turns off only when load current falls below its holding current (I_H = 150–340 mA). This autonomous operation simplifies PCB layout and reduces BOM count compared to active protection ICs.

How does the MMT05A230T3 differ from a standard TVS diode like P6SMB270A?

Unlike unidirectional TVS diodes such as P6SMB270A, the MMT05A230T3 is bidirectional, latches into low-impedance conduction (crowbar mode), and fails short-circuit-providing guaranteed post-failure protection. TVS diodes clamp without latching and may degrade after repeated surges. The MMT05A230T3 also offers superior dv/dt immunity (2000 V/µs vs. ~100 V/µs typical for TVS) and lower long-term wear-out risk.

Can the MMT05A230T3 be used in AC mains applications?

No-the MMT05A230T3 is specified for telecom secondary protection only (e.g., tip/ring lines), not primary AC mains. Its 265–280 V breakover voltage and 50 A surge rating are optimized for low-energy, high-impedance telecom surges-not high-energy utility faults. Using it on AC mains risks catastrophic failure due to excessive follow current; dedicated AC-rated TSPDs or GDTs are required instead.

What is the significance of the UL Registration E210057 for the MMT05A230T3?

UL Registration E210057 certifies that the MMT05A230T3 meets UL 1449 (Surge Protective Devices) construction and performance requirements for component-level surge protection. This registration streamlines end-equipment certification for North American telecom deployments, reducing validation time and cost. The MMT05A230T3 is not a standalone SPD but a recognized component enabling compliant system-level designs.