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

Diodes Incorporated FMMT497TA

Name: FMMT497TA
Brand: Diodes Incorporated
SKU: FMMT497TA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FMMT497TA

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

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

Datasheet:: FMMT497TA.pdf

Description:: TRANS NPN 300V 0.5A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:11,621

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Product details

Overview

FMMT497TA from Diodes Incorporated (formerly Zetex Semiconductors) is an NPN silicon planar high-voltage transistor in SOT-23 package, rated for 300 V V_CEO, 500 mA I_C, and 75 MHz f_T, designed for high-voltage switching in flyback converters, relay drivers, and pulse generators.

For engineers reviewing the FMMT497TA datasheet, FMMT497TA pinout, FMMT497TA application, or FMMT497TA equivalent, key selection criteria include V_CEO/V_CBO rating, h_FE consistency at 250 mA, V_CE(sat) under high-current switching, and SOT-23 thermal performance in high-reliability industrial power stages.

Technical Context

This device operates as a high-voltage NPN switch with robust secondary breakdown immunity, supporting pulsed operation up to 1 A I_CM and stable gain (h_FE = 20–300) across 1 mA–250 mA collector current. Its 5 pF C_obo and 75 MHz f_T enable fast turn-on/turn-off in high-frequency SMPS topologies.

The transistor features low V_CE(sat) (0.2 V @ 100 mA/10 mA, 0.3 V @ 250 mA/25 mA) and tight V_BE(sat) (1.0 V @ 250 mA/25 mA), ensuring predictable drive requirements and minimal conduction loss in high-side or low-side configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - supports primary-side switching in offline flyback converters up to 265 VAC input.
I_C	500 mA continuous - sufficient for driving small relays, solenoids, or gate resistors of downstream MOSFETs.
f_T	75 MHz - enables reliable operation in PWM circuits operating below 1 MHz with margin for layout parasitics.
V_CE(sat)	0.3 V @ 250 mA/25 mA - limits power dissipation to ≤75 mW during saturation, easing thermal design in SOT-23.
h_FE	20–300 - wide gain range accommodates both fixed-bias and active-feedback driver designs without gain compensation.
C_obo	5 pF @ 10 V - minimizes Miller effect in high-dV/dt applications such as snubberless flyback or capacitive load switching.
P_tot	500 mW @ T_amb = 25°C - defines maximum steady-state power handling before derating begins at elevated ambient temperatures.

Pinout & Package

Package: SOT-23 (3-lead plastic surface-mount). Dimensions conform to JEDEC TO-236AB standard: D = 2.80–3.04 mm, E = 2.10–2.64 mm, e = 0.95 mm pitch.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-side return path; must handle full load current and withstand reverse V_EB up to 5 V.
2 (Base)	Control input	Receives current-limited drive signal; requires ≥10 mA for full saturation at 250 mA collector load.
3 (Collector)	High-voltage output node	Switches up to 300 V; connects to inductive loads or transformer primaries; requires external snubbing if dV/dt exceeds 50 V/ns.

Key Features

Feature	Design Value
High-voltage blocking	300 V V_CEO and V_CBO - eliminates need for series-connected transistors in 230 VAC-derived supplies.
Fast switching	Turn-off time t_f = 228 ns - reduces switching losses in 100–500 kHz DC-DC converters.
Thermal stability	Operating junction temperature range –55°C to +150°C - supports deployment in automotive under-hood or industrial motor control enclosures.
Low leakage	I_CBO = 100 nA @ 250 V - ensures minimal standby current in always-on high-voltage bias networks.
SOT-23 footprint	Standardized 3-pin package - enables drop-in replacement in existing PCB layouts and compatibility with automated pick-and-place equipment.

Applications

Relay Driver Circuit

Flyback Converter Switch

Use Scenario: Driving 12 V/1 A electromagnetic relay coil from a 3.3 V microcontroller GPIO via base resistor.

IC Role / Device Role / Timing Role: High-voltage NPN switch providing galvanic isolation between logic and inductive load.

Use Value: 300 V V_CEO safely clamps relay coil flyback spikes; 0.3 V V_CE(sat) keeps power dissipation under 75 mW at full load.

Use Scenario: Primary-side switch in 5 W offline flyback converter for industrial sensor power supply.

IC Role / Device Role / Timing Role: Main energy-transfer switch cycling at 65 kHz, turning on/off transformer primary current.

Use Value: 75 MHz f_T and 228 ns t_f ensure clean square-wave switching with <5% duty-cycle distortion at target frequency.

Pulse Generator Output Stage

High-Voltage Logic Interface

Use Scenario: Generating 100 ns–1 µs pulses into 50 Ω load for test equipment trigger outputs.

IC Role / Device Role / Timing Role: Fast-switching NPN emitter-follower delivering high-voltage transient pulses.

Use Value: 53 ns t_d and 126 ns t_r support sub-200 ns rise/fall times; 5 pF C_obo minimizes capacitive loading on pulse-shaping network.

Use Scenario: Level-shifting TTL signals to interface with 100–250 V logic rails in PLC I/O modules.

IC Role / Device Role / Timing Role: Voltage-tolerant open-collector translator enabling bidirectional signal coupling.

Use Value: 5 V V_EBO and 300 V V_CBO allow safe operation across wide common-mode voltage swings without external protection diodes.

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
ZXTN25012CFH	V_CEO = 200 V, f_T = 150 MHz, SOT-23 package	Limited to ≤200 V applications; higher speed but lower voltage margin	Select when switching frequency >500 kHz and voltage stress <180 V is guaranteed.
MMBT4401	V_CEO = 40 V, I_C = 600 mA, h_FE = 100–300	Not suitable for >60 V circuits; lacks high-voltage safe operating area	Use only in low-voltage DC-DC or signal amplification where V_CE never exceeds 40 V.

Compared with ZXTN25012CFH and MMBT4401, FMMT497TA uniquely balances 300 V capability with SOT-23 form factor and proven reliability in sustained high-voltage switching-making it the sole choice for 230 VAC-derived flyback or relay drive where voltage margin is non-negotiable.

Availability

FMMT497TA is available at Aetrix Electronics and suitable for relay drivers, flyback converters, pulse generators, and high-voltage logic interfaces requiring stable component supply across industrial, instrumentation, and embedded power applications.

Supply support for FMMT497TA 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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal devices, with ISO 9001 and IATF 16949 certification and broad distribution through authorized channels.

FMMT497TA belongs to Diodes' legacy Zetex high-voltage transistor product line, engineered specifically for robustness in industrial power switching, where sustained 300 V operation and thermal resilience are mandatory.

FAQ

What is the maximum safe operating voltage for FMMT497TA in continuous DC mode?

The absolute maximum V_CEO is 300 V, but for reliable long-term operation in DC or low-frequency switching, derate to ≤240 V to maintain margin against transients and temperature-induced parameter drift. The SOA curve on page 4 of the datasheet confirms 240 V is sustainable at 100 mA with 1 s pulse width and no forced airflow.

Can FMMT497TA replace FMMT597 in complementary pair circuits?

No-FMMT497TA is NPN while FMMT597 is its PNP complement. They share identical voltage/current ratings and SOT-23 pinout (C-B-E), but polarity reversal means direct substitution would invert logic states and cause circuit failure unless board-level redesign accounts for emitter/collector swap and bias inversion.

Does FMMT497TA require a base resistor when driven by a 3.3 V MCU GPIO?

Yes-a series base resistor is mandatory to limit I_B to ≤200 mA and ensure proper saturation. For 250 mA I_C, h_FE ≥20 requires ≥12.5 mA I_B; with 3.3 V GPIO and 1.0 V V_BE(sat), a 180 Ω resistor sets I_B ≈ 12.8 mA, meeting design intent without exceeding base rating.

Is FMMT497TA RoHS-compliant and lead-free?

Yes-per Zetex's green compliance statement (page 6), all FMMT497 devices are RoHS-compliant and fully lead-free, meeting EU Directive 2011/65/EU. The SOT-23 package uses matte tin (Sn) termination, and no exemptions apply; full material declarations are available upon request from Diodes Incorporated.

FMMT497TA 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:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 300 V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 25mA, 250mA

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 80 @ 100mA, 10V

Power - Max:: 500 mW

Frequency - Transition:: 75MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

FMMT497TA FAQ

1.How can I place an order for FMMT497TA through Aetrix?

Please submit a Request for Quotation (RFQ) for FMMT497TA 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 FMMT497TA reliable?

The price and inventory of FMMT497TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT497TA is usually 5 days.

3.What payment methods are accepted for FMMT497TA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT497TA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FMMT497TA?

FMMT497TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FMMT497TA 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 FMMT497TA?

For technical support, including FMMT497TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT497TA requirements.

6.How does Aetrix verify that FMMT497TA is sourced from the original manufacturer or authorized distributors?

All FMMT497TA 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 FMMT497TA meets industry standards.

7.What is the process for return or replacement of FMMT497TA?

All FMMT497TA units undergo pre-shipment inspection (PSI). If there is an issue with FMMT497TA, 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 FMMT497TA part is unused and in its original packaging.

Return procedure for FMMT497TA:

1.Submit a request within 90 days.

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

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