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Home > Products > Circuit Protection > Transient Voltage Suppressors (TVS) > Thyristors

onsemi MMT10B350T3G

Name: MMT10B350T3G
Brand: onsemi
SKU: MMT10B350T3G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMT10B350T3G

Manufacturer:: onsemi

Category:: Thyristors

Package:: DO-214AA, SMB

Datasheet:: MMT10B350T3G.pdf

Description:: THYRISTOR 300V 100A DO-214AA

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Product details

Overview

MMT10B350T3G from onsemi is a high-voltage bidirectional thyristor surge protective device (TSPD) designed for secondary overvoltage protection in telecom line interfaces. It provides 350 V breakdown voltage, 400–412 V breakover voltage at +65°C, 100 A peak surge current (10 × 1000 µs), and fails short-circuit under overstress-ensuring continued protection integrity in customer-premises telecom equipment.

For engineers reviewing the MMT10B350T3G datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional clamping behavior, dv/dt immunity (2000 V/s), holding current (150–300 mA), off-state leakage (<5.0 µA at V_DM), and SMB package compatibility with telecom surge protection layouts.

Technical Context

The MMT10B350T3G operates as a crowbar-type protector: it remains non-conductive below its breakover voltage, then latches into low-impedance conduction upon transient-triggered turn-on and sustains conduction until surge current falls below its holding current (150–300 mA). Its bidirectional symmetry enables single-device protection of TIP/RING telecom lines without polarity concerns.

It meets regulatory requirements including ITU-T K.20/K.21, Bellcore GR-1089, IEC 60950, UL 1459/1950, and FCC Part 68. The device exhibits minimal voltage variation across surge amplitudes and rates, with a breakover voltage temperature coefficient of +0.12 V/°C and stable capacitance (≤85 pF at 1 MHz).

Key Specifications

Parameter	Value and Actual Design Meaning
Breakdown Voltage V_(BR)	350 V - Defines minimum DC blocking level before avalanche onset; sets baseline protection threshold for telecom line interface.
Breakover Voltage V_(BO)	400–412 V at +65°C - Actual clamping initiation point under AC transients; determines surge let-through voltage during protection event.
Peak Surge Current I_PPS1	100 A (10 × 1000 µs) - Maximum single-event surge energy handling capability under standard lightning waveform.
Holding Current I_H	150–300 mA - Minimum current required to sustain conduction; ensures automatic reset after surge decay.
Critical dv/dt	2000 V/s - Minimum rate-of-rise needed to trigger false turn-on; prevents spurious activation from line noise or ringing.
Off-State Leakage I_D2	≤5.0 µA at V_DM = 300 V - Low standby power loss and minimal signal loading on protected line.
On-State Voltage V_T	1.82 V typ. at 1.0 A - Low conduction loss during crowbar state; reduces thermal stress during sustained surges.

Pinout & Package

MMT10B350T3G is housed in an SMB package (JEDEC DO-214AA), surface-mount, bidirectional, polarity-free case with two terminals: MT1 and MT2. No cathode/anode designation applies; both terminals are functionally symmetric.

Pin/Terminal	Circuit Role	Design Meaning
MT1	Main Terminal 1	One of two symmetrical, interchangeable surge current paths; connects to TIP or RING line without polarity constraint.
MT2	Main Terminal 2	Second symmetrical terminal; completes bidirectional crowbar path between telecom line pair and ground reference.

Key Features

Feature	Design Value
Fail-safe short-circuit mode	Guarantees continued protection integrity by latching low-impedance path when overstressed-prevents open-circuit failure modes common in MOVs.
Bidirectional protection	Single-device coverage of both polarities eliminates need for back-to-back diodes or dual-component solutions in TIP/RING telecom interfaces.
Stable voltage limit vs. dv/dt	Breakover voltage varies <±5% across 200–2000 V/s input rates-ensures predictable clamping regardless of transient rise time.
Pb-free SMB package	RoHS-compliant surface-mount footprint (4.57 × 3.81 × 2.11 mm) compatible with automated assembly and reflow profiles up to 260°C.

Applications

DSL Line Interface Protection	Voice over IP (VoIP) Gateway
Use Scenario: Protecting copper-pair DSLAM and CPE interfaces against induced lightning surges and power cross events. IC Role / Device Role / Timing Role: Crowbar-type primary surge clamp placed between line transformer secondary and codec IC input. Use Value: Withstands 100 A 10/1000 µs surges while maintaining ≤350 V standoff-preserving signal integrity and preventing codec latch-up.	Use Scenario: Secondary surge protection on analog telephone line ports of VoIP adapters and residential gateways. IC Role / Device Role / Timing Role: Bidirectional overvoltage limiter installed upstream of PPTC and line driver ICs. Use Value: Fails short-circuit under extreme stress, ensuring downstream components remain protected even after device degradation.
ISDN BRI Interface	Central Office Line Card
Use Scenario: Overvoltage suppression on 2B+D ISDN basic rate interfaces exposed to outdoor plant wiring. IC Role / Device Role / Timing Role: High-energy crowbar element in series with line transformer and hybrid circuit. Use Value: 400–412 V breakover voltage aligns with ITU-T K.21 Class B limits-enabling compliance without external voltage dividers.	Use Scenario: Telecom line card protection in carrier-class access systems requiring long-term reliability and regulatory certification. IC Role / Device Role / Timing Role: Secondary protector coordinated with gas discharge tube (GDT) front-end for staged surge handling. Use Value: 2000 V/s dv/dt immunity prevents misfiring during GDT follow-on current oscillations-maintaining system uptime.

DSL Line Interface Protection

Voice over IP (VoIP) Gateway

Use Scenario: Protecting copper-pair DSLAM and CPE interfaces against induced lightning surges and power cross events.

IC Role / Device Role / Timing Role: Crowbar-type primary surge clamp placed between line transformer secondary and codec IC input.

Use Value: Withstands 100 A 10/1000 µs surges while maintaining ≤350 V standoff-preserving signal integrity and preventing codec latch-up.

Use Scenario: Secondary surge protection on analog telephone line ports of VoIP adapters and residential gateways.

IC Role / Device Role / Timing Role: Bidirectional overvoltage limiter installed upstream of PPTC and line driver ICs.

Use Value: Fails short-circuit under extreme stress, ensuring downstream components remain protected even after device degradation.

ISDN BRI Interface

Central Office Line Card

Use Scenario: Overvoltage suppression on 2B+D ISDN basic rate interfaces exposed to outdoor plant wiring.

IC Role / Device Role / Timing Role: High-energy crowbar element in series with line transformer and hybrid circuit.

Use Value: 400–412 V breakover voltage aligns with ITU-T K.21 Class B limits-enabling compliance without external voltage dividers.

Use Scenario: Telecom line card protection in carrier-class access systems requiring long-term reliability and regulatory certification.

IC Role / Device Role / Timing Role: Secondary protector coordinated with gas discharge tube (GDT) front-end for staged surge handling.

Use Value: 2000 V/s dv/dt immunity prevents misfiring during GDT follow-on current oscillations-maintaining system uptime.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SM10T350	Unidirectional TSPD; requires back-to-back configuration for bidirectional protection; lower 75 A surge rating (10 × 1000 µs).	Suitable only where polarity is fixed and space allows dual placement; not drop-in for TIP/RING telecom pairs.	Select only if unidirectional line architecture exists and PCB layout permits dual placement.
BT139-600E	Standard triac with 600 V blocking voltage; no specified surge rating, dv/dt immunity, or telecom compliance documentation.	Lacks regulatory validation for telecom surge standards (K.20/K.21); higher holding current (≥500 mA) risks incomplete reset.	Not recommended for certified telecom designs; use only in non-regulated industrial control where surge profile is known and benign.

Compared with SM10T350 and BT139-600E, the MMT10B350T3G delivers verified bidirectional 100 A surge handling, K.21-compliant breakover characteristics, and fail-safe shorting-making it the only option qualified for secondary protection in FCC Part 68 and ITU-T certified telecom equipment.

Availability

MMT10B350T3G is available at Aetrix Electronics and suitable for DSL line interface protection, VoIP gateway design, ISDN BRI termination, and central office line card development requiring stable component supply and long-lifecycle support.

Supply support for MMT10B350T3G 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, and communications markets.

The MMT10B350T3G belongs to onsemi's Thyristor Surge Protector (TSPD) product line, engineered specifically for secondary overvoltage protection in telecom infrastructure-balancing high surge robustness, regulatory compliance, and fail-safe reliability.

FAQ

What is the primary function of the MMT10B350T3G in telecom circuits?

The MMT10B350T3G functions as a bidirectional crowbar-type surge protector that triggers at ~400 V and clamps high-energy transients-such as lightning-induced surges-by switching to low-impedance conduction. It remains latched until current falls below its holding current (150–300 mA), ensuring robust secondary protection in TIP/RING telecom interfaces. The MMT10B350T3G is validated for Bellcore GR-1089 and ITU-T K.20/K.21 compliance.

Does the MMT10B350T3G have polarity markings or directional requirements?

No-the MMT10B350T3G is a fully bidirectional device with no anode/cathode designation. Its MT1 and MT2 terminals are electrically symmetric, allowing direct placement across any differential telecom line pair (e.g., TIP–RING) without orientation constraints. This eliminates routing errors and simplifies layout in dual-line protection schemes.

What is the maximum operating temperature range for the MMT10B350T3G?

The MMT10B350T3G supports continuous operation from −40°C to +125°C in both blocking and conducting states. During surge events, its junction temperature may reach +175°C momentarily-within its rated overload limit. This wide range ensures reliable performance in uncontrolled environments like customer-premises telecom cabinets and outdoor line cards.

How does the MMT10B350T3G differ from MOV-based protectors?

Unlike metal-oxide varistors (MOVs), the MMT10B350T3G exhibits no wear-out mechanism under repeated surges, maintains stable clamping voltage across varying dv/dt, and fails short-circuit-preventing unprotected operation. MOVs degrade with each event and may fail open, leaving downstream circuitry vulnerable. The MMT10B350T3G also offers tighter voltage tolerance and superior longevity in telecom applications.

Is the MMT10B350T3G RoHS compliant and lead-free?

Yes-the "G" suffix in MMT10B350T3G explicitly denotes a Pb-free (lead-free) version, qualified per JEDEC J-STD-020 moisture sensitivity level 1 and compatible with standard SnPb and lead-free reflow profiles. Its SMB package meets RoHS Directive 2011/65/EU and is marked with the Pb-free identifier per onsemi's packaging specification.

MMT10B350T3G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Package/Case:: DO-214AA, SMB

Series:: -

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Voltage - Breakover:: 400V

Voltage - Off State:: 300V

Voltage - On State:: 5 V

Current - Peak Pulse (8/20µs):: -

Current - Peak Pulse (10/1000µs):: 100 A

Current - Hold (Ih):: 150 mA

Number of Elements:: 1

Capacitance:: 85pF

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SMB

MMT10B350T3G FAQ

1.How can I place an order for MMT10B350T3G through Aetrix?

Please submit a Request for Quotation (RFQ) for MMT10B350T3G on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MMT10B350T3G reliable?

The price and inventory of MMT10B350T3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMT10B350T3G is usually 5 days.

3.What payment methods are accepted for MMT10B350T3G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMT10B350T3G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMT10B350T3G?

MMT10B350T3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMT10B350T3G order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MMT10B350T3G?

For technical support, including MMT10B350T3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMT10B350T3G requirements.

6.How does Aetrix verify that MMT10B350T3G is sourced from the original manufacturer or authorized distributors?

All MMT10B350T3G products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MMT10B350T3G meets industry standards.

7.What is the process for return or replacement of MMT10B350T3G?

All MMT10B350T3G units undergo pre-shipment inspection (PSI). If there is an issue with MMT10B350T3G, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MMT10B350T3G part is unused and in its original packaging.

Return procedure for MMT10B350T3G:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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