onsemi MMT05A230T3

Overview

MMT05A230T3 from onsemi is a bidirectional thyristor surge protective device (TSPD) designed for secondary overvoltage protection in telecom line interfaces. It provides 265–280 V breakover voltage, 50 A peak surge current (10 × 1000 µs), 2000 V/µs critical dv/dt rating, and fails short-circuit under overstress-used in customer-premises telecom equipment meeting Telcordia GR-1089, ITU K.20/K.21, IEC 60950, and FCC Part 68.

For engineers reviewing the MMT05A230T3 datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional clamping behavior, holding current (150–340 mA), off-state leakage (<2.0 µA at 50 V), thermal stability up to +125°C operating junction temperature, and SMA package compatibility with SMT assembly processes.

Technical Context

The MMT05A230T3 operates as a breakover-triggered crowbar protector: it remains high-impedance until transient voltage exceeds its bidirectional breakover threshold (~265–280 V), then latches into low-impedance conduction until surge current falls below its holding current (≥150 mA). Its fail-safe short-circuit mode prevents continued unprotected operation after overstress.

Designed for telecom secondary protection, it interfaces directly across TIP/RING lines with polymeric PTC (PPTC) current limiting upstream. Its 22–50 pF capacitance at 1 MHz ensures minimal signal distortion on voice-grade lines, and its 2000 V/µs dv/dt immunity prevents false triggering from fast transients.

Key Specifications

Pinout & Package

SMA package (Case 403D-02), surface-mount, bidirectional-no polarity marking required. Terminals MT1 and MT2 are functionally identical and interchangeable for TIP/RING line placement.

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-short reliability, and telecom-specific dv/dt immunity-making it the only option qualified for Telcordia GR-1089 Zone 3 secondary protection in TIP/RING configurations.

Availability

MMT05A230T3 is available at Aetrix Electronics and suitable for DSL line interface protection, voice POTS line protection, and Telcordia GR-1089 Zone 3 certified telecom equipment 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 focused on energy-efficient electronics, delivering silicon solutions for automotive, industrial, cloud, and communications markets.

The MMT05A230T3 belongs to onsemi's Thyristor Surge Protector (TSPD) product line, engineered specifically for secondary overvoltage protection in telecom infrastructure and customer-premises equipment compliant with Telcordia, ITU, and IEC standards.

FAQ

What is the primary function of the MMT05A230T3 in a telecom line interface?

The MMT05A230T3 functions as a bidirectional thyristor surge protective device (TSPD) that clamps transient overvoltages on TIP/RING lines by switching into a low-impedance state when voltage exceeds ~265 V. It remains latched until surge current drops below its holding current (≥150 mA), providing robust secondary protection in telecom equipment such as DSL modems and VoIP adapters. The MMT05A230T3 is explicitly rated for Telcordia GR-1089 Zone 3 and ITU-T K.21 compliance.

Does the MMT05A230T3 have polarity-sensitive terminals?

No-the MMT05A230T3 is a fully bidirectional device with interchangeable MT1 and MT2 terminals. Its SMA package (Case 403D-02) has no polarity marking, enabling direct placement across balanced telecom lines without orientation constraints. This symmetry is confirmed in the official datasheet's marking diagram and electrical characteristics table, which states "Devices are bidirectional. All electrical parameters apply to forward and reverse polarities." The MMT05A230T3 thus simplifies PCB layout for TIP/RING protection.

What is the maximum surge current rating for the MMT05A230T3, and under what test condition?

The MMT05A230T3 is rated for 50 A peak pulse surge current under the 10 × 1000 µs double-exponential waveform condition (IPPS4), tested at controlled temperature in the SMA package. This rating is validated per IEC 61000-4-5 and aligns with Telcordia GR-1089 Zone 3 requirements. The MMT05A230T3 also supports higher short-duration surges: 150 A (8 × 20 µs), 100 A (10 × 160 µs), and 70 A (10 × 560 µs), all specified in the official datasheet.

How does the MMT05A230T3 behave when subjected to a destructive overvoltage event?

When overstressed beyond its ratings, the MMT05A230T3 fails in a short-circuit mode-ensuring continued current limiting via upstream protection (e.g., PPTC) and preventing uncontrolled operation. This fail-safe behavior is explicitly documented in the datasheet: "Fail−Safe, Shorts When Overstressed, Preventing Continued Unprotected Operation." Unlike MOVs or GDTs, this hard short preserves system-level safety and meets Telcordia GR-1089 fault containment requirements. The MMT05A230T3's design intentionally avoids open-circuit failure modes.

What regulatory standards does the MMT05A230T3 help equipment meet?

The MMT05A230T3 is designed to support compliance with Telcordia GR-1089 (Zone 3), ITU-T K.20 and K.21, IEC 60950-1, and FCC Part 68. These standards govern surge immunity, insulation coordination, and safety for telecom terminal equipment installed at customer premises. The MMT05A230T3's 50 A surge rating, bidirectional clamping, and fail-short behavior are directly aligned with these requirements-as stated in the official datasheet's "Preferred Devices" section and application diagrams.