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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

Diodes Incorporated FMMT459TC

Name: FMMT459TC
Brand: Diodes Incorporated
SKU: FMMT459TC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FMMT459TC

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: FMMT459TC.pdf

Description:: TRANS NPN 450V 0.15A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,324

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Product details

Overview

FMMT459TC from Diodes Incorporated is a 500V NPN high-voltage transistor in SOT23 package, designed for off-line switching and RCD snubber circuits. It delivers 150mA continuous collector current, 500V collector-emitter breakdown voltage (BV_CEV), and low 75mV V_CE(sat) at 50mA/6mA drive-enabling efficient high-voltage switching in emergency lighting and telecom line protection.

For engineers reviewing the FMMT459TC datasheet, FMMT459TC pinout, FMMT459TC application, or FMMT459TC equivalent, key selection criteria include verified 500V BV_CEV, AEC-Q101 qualification, SOT23 thermal performance (R_θJA = 155°C/W), and reverse-blocking capability (BVECV = 6V) in high-reliability power control designs.

Technical Context

This NPN bipolar junction transistor operates with a minimum h_FE of 50 at 30mA and up to 120 at 50mA, supporting stable current gain across -55°C to +150°C. Its 50MHz transition frequency (f_T) and 5pF output capacitance enable fast switching in flyback and PFC disable applications.

The device features dual breakdown ratings: 500V BV_CEV under active base control and 450V BV_CEO with open-base configuration-critical for robustness in unregulated high-voltage rails. Reverse emitter-collector blocking (BVECV ≥ 6V) allows bidirectional transient suppression in telecom line switches.

Key Specifications

Parameter	Value and Actual Design Meaning
BV_CEV	500 V - Ensures reliable operation in 400V AC-derived DC bus applications without avalanche stress
I_C (continuous)	150 mA - Supports sustained current in PFC disable and piezo driver stages
V_CE(sat)	75 mV @ 50mA/6mA - Minimizes conduction loss and self-heating in compact SOT23 layout
h_FE	50–120 - Provides predictable base drive requirements across industrial temperature range
f_T	50 MHz - Enables clean turn-on/turn-off in sub-1µs timing-critical snubber circuits
R_θJA	155 °C/W - Allows 806mW pulse power dissipation on standard FR4 with 25mm² copper pad
BVECV	6 V - Permits safe reverse-biased operation during negative transients in protected line switching

Pinout & Package

Package: SOT23 - Surface-mount plastic package with matte tin-plated leads, moisture sensitivity level 1, and UL 94V-0 flammability rating. Weight: 0.008 g.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for base drive; connects to ground or return path in high-side switch configurations
2 (Base)	Control input	Accepts TTL/CMOS-compatible drive; requires ≤200mA peak current per absolute max rating
3 (Collector)	High-voltage output node	Handles 500V blocking; soldered to thermal pad for enhanced heat transfer in power-dense layouts

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD (HBM 4kV)
Green compound packaging	Halogen- and antimony-free molding compound (<900ppm Br+Cl, <1000ppm Sb)
Reverse emitter-collector blocking	6V BVECV rating enables use in bidirectional transient clamping circuits
Low thermal resistance	194°C/W R_θJL from junction to collector lead supports localized heatsinking in SOT23 footprint
High-voltage safe operating area	DC and pulsed SOA curves validated to 500V/150mA, enabling design margin in offline PSUs

Applications

Emergency Lighting Control

Telecom Line Protection

Use Scenario: High-voltage switching in battery-backed LED drivers during AC mains failure.

IC Role / Device Role / Timing Role: NPN switch controlling primary-side current to boost converter during brownout conditions.

Use Value: 500V BV_CEV withstands rectified 380V DC bus; low V_CE(sat) reduces thermal load in sealed enclosures.

Use Scenario: Overvoltage protection on analog telephone line interfaces exposed to lightning surges.

IC Role / Device Role / Timing Role: Fast-acting crowbar element triggered by transient detector circuitry.

Use Value: 3450ns turn-off time ensures rapid fault isolation; BVECV ≥ 6V blocks induced negative spikes.

PFC Disable Switch

Piezo Actuator Driver

Use Scenario: Disabling power factor correction stage during light-load conditions to improve efficiency.

IC Role / Device Role / Timing Role: High-voltage series switch placed between bridge rectifier and PFC controller input.

Use Value: 625mW steady-state power dissipation accommodates intermittent duty cycle without derating.

Use Scenario: Driving high-impedance piezoelectric elements requiring fast voltage transitions.

IC Role / Device Role / Timing Role: Voltage amplifier stage converting logic-level pulses into ±100V swing outputs.

Use Value: 50MHz f_T and 5pF C_obo support >100kHz actuation frequencies with minimal phase lag.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZTX450	BV_CEO = 300V; h_FE min = 100; SOT23-3 package	Limited to ≤300V systems; higher gain reduces base drive burden	Select when 300V rating suffices and tighter h_FE tolerance is required
MMBT5551	BV_CEO = 160V; I_C = 600mA; TO-236AB package	Lower voltage rating but higher current capacity; not AEC-Q101 qualified	Choose for cost-sensitive non-automotive 120VAC applications needing higher I_C

Compared with ZTX450 and MMBT5551, FMMT459TC uniquely combines 500V blocking, AEC-Q101 qualification, and SOT23 thermal performance-making it the only option for automotive-grade offline switching above 400V DC.

Availability

FMMT459TC is available at Aetrix Electronics and suitable for emergency lighting control, telecom line protection, and PFC disable switching requiring stable component supply across automotive, industrial, and telecom end markets.

Supply support for FMMT459TC 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management and signal integrity solutions for automotive, industrial, and consumer applications.

FMMT459TC belongs to Diodes' high-voltage transistor product line, engineered specifically for robust switching in off-line power supplies, surge-protected communication interfaces, and safety-critical lighting systems.

FAQ

What is the maximum allowable collector-emitter voltage for continuous operation?

The FMMT459TC has a BV_CEO rating of 450V at I_C = 1mA, which defines its maximum continuous collector-emitter voltage with open base. For active base-controlled operation, BV_CEV is rated at 500V-validating use in 400V DC bus applications with design margin. Derating is required above +25°C per the published thermal curve.

Does FMMT459TC support reverse-biased operation between emitter and collector?

Yes-FMMT459TC specifies BVECV ≥ 6V, meaning it can block up to 6V in reverse emitter-collector polarity. This capability is confirmed in the Electrical Characteristics table and enables use in bidirectional transient suppression circuits, such as telecom line protectors where negative surges occur.

How does the SOT23 package affect thermal performance in high-power switching?

In the SOT23 package, FMMT459TC achieves R_θJA = 155°C/W under pulsed conditions (t ≤ 5 sec) on 25mm² 1oz copper. Its R_θJL = 194°C/W allows direct thermal coupling to PCB copper pours via the collector lead, making it viable for intermittent 806mW pulses-critical for snubber and PFC disable functions.

Is FMMT459TC suitable for automotive applications?

Yes-FMMT459TC is explicitly qualified to AEC-Q101 standards, covering stress tests including HTGB, HTRB, temperature cycling, and ESD (HBM 4kV). Its -55°C to +150°C operating range and green, halogen-free construction meet automotive electronics requirements for under-hood and body-control modules.

FMMT459TC Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 150 mA

Voltage - Collector Emitter Breakdown (Max):: 450 V

Vce Saturation (Max) @ Ib, Ic:: 90mV @ 6mA, 50mA

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 50 @ 30mA, 10V

Power - Max:: 625 mW

Frequency - Transition:: 50MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

FMMT459TC FAQ

1.How can I place an order for FMMT459TC through Aetrix?

Please submit a Request for Quotation (RFQ) for FMMT459TC 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 FMMT459TC reliable?

The price and inventory of FMMT459TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT459TC is usually 5 days.

3.What payment methods are accepted for FMMT459TC?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT459TC transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FMMT459TC?

FMMT459TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FMMT459TC 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 FMMT459TC?

For technical support, including FMMT459TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT459TC requirements.

6.How does Aetrix verify that FMMT459TC is sourced from the original manufacturer or authorized distributors?

All FMMT459TC 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 FMMT459TC meets industry standards.

7.What is the process for return or replacement of FMMT459TC?

All FMMT459TC units undergo pre-shipment inspection (PSI). If there is an issue with FMMT459TC, 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 FMMT459TC part is unused and in its original packaging.

Return procedure for FMMT459TC:

1.Submit a request within 90 days.

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

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