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

Diodes Incorporated FMMT491QTA

Name: FMMT491QTA
Brand: Diodes Incorporated
SKU: FMMT491QTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FMMT491QTA

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

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

Datasheet:: FMMT491QTA.pdf

Description:: TRANS NPN 60V 1A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,516

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Product details

Overview

FMMT491QTA from Diodes Incorporated is a 60V NPN medium-power bipolar junction transistor in SOT23 package, rated for 1A continuous collector current, 2A peak pulse current, and 500mW power dissipation, with V_CE(SAT) = 160mV at I_C = 1A/ I_B = 100mA, and qualified to AEC-Q101 for automotive engine control modules.

For engineers reviewing the FMMT491QTA datasheet, FMMT491QTA pinout, FMMT491QTA application, or FMMT491QTA equivalent, key selection criteria include guaranteed V_CEO ≥ 60V, h_FE ≥ 80 at 1A, R_θJA = 250°C/W on standard FR-4, ESD HBM rating of 4kV, and automotive-grade traceability under PPAP.

Technical Context

This NPN BJT operates as a medium-power switching device with low saturation voltage (160mV max at 1A), enabling efficient load control in 12V/24V automotive subsystems. Its h_FE remains ≥30 up to 2A, supporting robust current gain hold-up during transient loads.

Thermally, it delivers 500mW dissipation on a 15mm × 15mm 1oz copper pad, with R_θJA = 250°C/W and R_θJL = 197°C/W - optimized for lead-attached thermal relief in compact SMT layouts.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60V - supports operation across full 24V automotive battery range with margin against load dump transients
I_C (continuous)	1A - enables direct drive of solenoids, relays, and LED arrays without external buffering
V_CE(SAT)	160mV max at I_C=1A/I_B=100mA - limits conduction loss to ≤160mW, reducing thermal stress in sealed enclosures
h_FE	80 min at I_C=1A - ensures reliable base drive margin with standard microcontroller GPIO outputs
f_T	150MHz - supports fast switching (>100kHz PWM) in DC-DC pre-regulator and lamp dimming circuits
ESD HBM	4,000V - meets stringent handling requirements for automated SMT assembly in Tier-1 production lines
R_θJA	250°C/W - defines thermal derating slope: power must be reduced by 4mW/°C above +25°C ambient on standard PCB layout

Pinout & Package

Package: SOT23 (Type DN), surface-mount plastic case with matte tin-plated leads, UL 94V-0 rated, moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-side return path; requires low-inductance routing for PWM stability
2 (Base)	Control input	Driven by MCU GPIO or logic-level signal; 100mA max base current enables direct drive from most 3.3V/5V outputs
3 (Collector)	High-side load connection	Routes switched power to load; collector lead serves as primary thermal path to PCB copper

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive underhood applications including temperature cycling (-55°C to +150°C) and mechanical shock
Low V_CE(SAT)	160mV max at 1A reduces I²R losses by >40% vs. legacy 300mV devices, lowering board-level thermal density
h_FE characterization up to 2A	Guaranteed gain ≥30 at 2A enables predictable switching behavior during surge currents (e.g., motor startup)
Lead-free & halogen-free	Meets RoHS 3 and JESD22-A114 ESD standards without compromising solderability or long-term reliability

Applications

Engine Control Unit (ECU) Injector Driver

Automotive HVAC Blower Motor Control

Use Scenario: Switching 12V fuel injector coils with 2ms pulse width and 10Hz repetition rate in gasoline direct injection systems.

IC Role / Device Role / Timing Role: NPN switch providing low-loss, high-speed current sinking for precise fuel metering.

Use Value: V_CE(SAT) ≤160mV minimizes coil heating and extends solenoid life; f_T ≥150MHz ensures clean turn-off edge for accurate pulse width control.

Use Scenario: Controlling brushed DC blower motor speed via PWM in climate control modules.

IC Role / Device Role / Timing Role: Medium-power switching element in low-side motor driver stage.

Use Value: 1A continuous rating handles 800mA nominal motor current with 2× surge margin; AEC-Q101 qualification ensures operation at +105°C under dash conditions.

LED Headlamp Dimming Circuit

Body Control Module (BCM) Relay Interface

Use Scenario: PWM-driven current regulation for adaptive front-lighting system (AFS) LED strings.

IC Role / Device Role / Timing Role: High-efficiency linear/PWM hybrid switch managing 500mA–1A LED loads.

Use Value: h_FE ≥80 at 1A allows single-stage base drive from CAN/LIN transceiver I/O; low V_CE(SAT) prevents thermal runaway during 100% duty cycle.

Use Scenario: Driving 12V automotive relays (e.g., window lift, door lock) from microcontroller outputs.

IC Role / Device Role / Timing Role: General-purpose NPN interface transistor isolating MCU pins from inductive relay coils.

Use Value: BV_CEO = 60V withstands relay coil flyback spikes up to 55V; ESD HBM = 4kV protects against assembly-line static discharge.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZXTN25050DFHTA	Higher V_CEO (50V), lower V_CE(SAT) (120mV), but h_FE drops to 40 at 1A	Preferred for higher-efficiency 12V-only systems where gain margin is less critical	Select when thermal budget is tighter and base drive capability exceeds 100mA
MMBT4401-7-F	Lower V_CEO (40V), same SOT23 package, but only 600mW PD and no AEC-Q101 qualification	Suitable for non-automotive industrial controls with <40V supply rails	Choose only for cost-sensitive consumer or commercial designs lacking automotive compliance needs

Compared with ZXTN25050DFHTA and MMBT4401-7-F, FMMT491QTA uniquely balances 60V breakdown, AEC-Q101 reliability, and 1A/160mV performance - making it the only option qualified for underhood automotive switching where both voltage margin and thermal robustness are mandatory.

Availability

FMMT491QTA is available at Aetrix Electronics and suitable for automotive engine control units, HVAC blower motor drivers, LED headlamp dimming circuits, and body control module relay interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for FMMT491QTA 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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The FMMT series targets automotive-qualified medium-power transistors, designed specifically for high-reliability switching in engine management, chassis, and comfort systems where AEC-Q101 compliance and thermal resilience are mandatory.

FAQ

What is the maximum allowable junction temperature for FMMT491QTA?

The absolute maximum operating junction temperature is +150°C, with storage temperature ranging from –55°C to +150°C. Derating begins at +25°C ambient: power dissipation must decrease by 4mW per °C rise above this point on a standard 15mm × 15mm 1oz copper PCB.

Does FMMT491QTA require a heatsink in typical automotive applications?

No external heatsink is required when mounted on a 15mm × 15mm 1oz copper pad. Its R_θJA = 250°C/W and 500mW rating allow safe operation at up to +105°C ambient in sealed enclosures - verified per AEC-Q101 thermal cycling tests.

Can FMMT491QTA replace FMMT491QT in production?

Yes - FMMT491QTA is the tape-and-reel variant (3,000 pcs/reel, 8mm tape width) of the same AEC-Q101-qualified die used in FMMT491QT. Marking "491" and SOT23 (DN) package dimensions are identical; only packaging differs.

What is the complementary PNP part for FMMT491QTA?

The officially designated complementary PNP is FMMT591Q, sharing identical SOT23 package, AEC-Q101 qualification, 60V V_CEO, 1A I_C, and matching h_FE and V_CE(SAT) specifications - enabling balanced push-pull or H-bridge designs in automotive motor control.

FMMT491QTA 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):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 100mA, 1A

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 500mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 150MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

FMMT491QTA FAQ

1.How can I place an order for FMMT491QTA through Aetrix?

Please submit a Request for Quotation (RFQ) for FMMT491QTA 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 FMMT491QTA reliable?

The price and inventory of FMMT491QTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT491QTA is usually 5 days.

3.What payment methods are accepted for FMMT491QTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT491QTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FMMT491QTA?

FMMT491QTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FMMT491QTA 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 FMMT491QTA?

For technical support, including FMMT491QTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT491QTA requirements.

6.How does Aetrix verify that FMMT491QTA is sourced from the original manufacturer or authorized distributors?

All FMMT491QTA 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 FMMT491QTA meets industry standards.

7.What is the process for return or replacement of FMMT491QTA?

All FMMT491QTA units undergo pre-shipment inspection (PSI). If there is an issue with FMMT491QTA, 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 FMMT491QTA part is unused and in its original packaging.

Return procedure for FMMT491QTA:

1.Submit a request within 90 days.

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

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