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Diodes Incorporated FMMT494QTA
- Part No.:
- FMMT494QTA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
FMMT494QTA.pdf
- Description:
- TRANS NPN 120V 1A SOT-23-3
- Quantity:
- Payment:
- Shipping:
Inventory:23,467
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Product details
Overview
FMMT494QTA from Diodes Incorporated is a 120V NPN silicon planar medium-power bipolar junction transistor (BJT) in SOT23 package, rated for 1A continuous collector current, 500mW power dissipation, and qualified to AEC-Q101 for automotive use. It delivers high-current gain stability up to 1A (hFE ≥ 20 at IC = 1A), supports 140V VCBO, and operates across –55°C to +150°C for under-hood engine control modules.
For engineers reviewing the FMMT494QTA datasheet, FMMT494QTA pinout, FMMT494QTA application, or FMMT494QTA equivalent, key selection criteria include its 120V VCEO, 2A peak pulse rating, low VCE(sat) (≤300 mV @ 500mA/50mA), AEC-Q101 qualification, and SOT23 thermal performance on 15mm × 15mm FR4 with 1 oz copper.
Technical Context
This NPN BJT employs a planar silicon structure optimized for medium-power switching in harsh environments. Its BVCEO = 120V and RθJA = 250°C/W enable reliable operation in 12V/24V automotive subsystems where voltage transients and ambient temperature extremes occur.
The device features characterized hFE down to 20 at 1A, ensuring predictable current amplification in saturated switch applications. Its ESD robustness (HBM = 4 kV) and halogen/antimony-free "Green" construction meet Tier-1 automotive supply chain requirements without derating penalties.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 120 V - Withstands 120V collector-emitter blocking voltage in switched-off state, suitable for 24V system load switching with margin. |
| IC (continuous) | 1 A - Supports steady-state load currents up to 1A, e.g., fuel injector drivers or fan motor controls. |
| PD | 500 mW - Maximum steady-state power dissipation on standard 15mm × 15mm FR4 PCB with 1 oz copper. |
| hFE @ IC = 1A | ≥20 - Ensures sufficient base drive efficiency and predictable saturation behavior at full rated current. |
| VCE(sat) | ≤300 mV @ IC = 500mA, IB = 50mA - Limits conduction loss and self-heating during active switching in power interface circuits. |
| fT | 100 MHz - Enables stable operation in high-speed digital switching (e.g., PWM frequencies ≤ 10 MHz) with adequate gain margin. |
| ESD HBM | 4,000 V - Meets JEDEC Class 3A for handling robustness in automated assembly and field-replaceable modules. |
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-impedance layout to minimize VEB drop during turn-on. |
| 2 (Base) | Control input | Receives current-limited drive (max 200 mA); logic-level compatible with 3.3V/5V microcontrollers via series resistor. |
| 3 (Collector) | High-side load connection | Interfaces directly to inductive loads (e.g., solenoids) up to 120V; requires flyback diode for energy recirculation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTOL, and ESD stress per JESD47. |
| Lead-free & "Green" | Halogen-free (<900 ppm Br/Cl, <1000 ppm Sb), RoHS-compliant construction for eco-sensitive supply chains. |
| High VCEO hold-up | Maintains safe cutoff at 120V under transient overvoltage conditions common in 24V truck/bus electrical systems. |
| Stable hFE at 1A | Guaranteed minimum gain of 20 ensures consistent base current calculation across production lots and temperature range. |
Applications
| Engine Control Unit (ECU) Injector Driver | Automotive HVAC Blower Motor Switch |
|---|---|
Use Scenario: Driving 12V fuel injectors with 5–10 ms pulse width modulation in gasoline direct injection systems. IC Role / Device Role / Timing Role: NPN switch controlling high-side injector coil current; operates in saturated mode with fast turn-on/turn-off. Use Value: 120V VCEO withstands battery dump transients; 1A IC handles peak coil current; low VCE(sat) minimizes heat generation during extended duty cycles. | Use Scenario: Controlling brushed DC blower motors in climate control systems with variable speed via PWM. IC Role / Device Role / Timing Role: Low-side switching element interfacing MCU GPIO to motor return path; handles bidirectional back-EMF spikes. Use Value: AEC-Q101 qualification ensures longevity in under-dash thermal environments; 150°C TJ max enables operation near heater cores without derating. |
| Body Control Module (BCM) Lamp Driver | Commercial Vehicle ABS Solenoid Interface |
Use Scenario: Switching LED headlamp arrays and incandescent parking lights in centralized lighting controllers. IC Role / Device Role / Timing Role: Medium-power discrete switch replacing relays; driven by CAN/LIN node microcontroller outputs. Use Value: 500mW PD allows direct PCB mounting without heatsink; SOT23 footprint saves space vs. TO-220 alternatives in compact BCM designs. | Use Scenario: Driving ABS hydraulic modulator solenoids requiring precise 12V/24V actuation pulses during braking events. IC Role / Device Role / Timing Role: High-voltage NPN driver stage amplifying microcontroller output to energize inductive solenoid coils. Use Value: 140V VCBO and 2A ICM support fast, high-energy solenoid actuation while surviving load-dump surges per ISO 7637-2. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN medium-power switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ZXTN25040DFHTA | Higher VCEO (150V), lower RθJA (200°C/W), but hFE not specified above 500mA. | Better thermal performance on minimal copper; less predictable gain at full 1A load. | Select when board space is constrained and thermal margin is critical, but verify gain stability at target IC. |
| BC817-40,215 | Lower VCEO (45V), higher hFE (250–630), but not AEC-Q101 qualified. | Suitable for non-automotive 5V/12V logic-level switching only; lacks automotive reliability validation. | Choose only for cost-sensitive industrial or consumer applications where AEC-Q101 is not required. |
Compared with ZXTN25040DFHTA and BC817-40,215, the FMMT494QTA uniquely balances 120V ruggedness, AEC-Q101 compliance, and verified hFE ≥20 at 1A-making it the preferred choice for automotive power interface stages where both voltage margin and current gain predictability are mandatory.
Availability
FMMT494QTA is available at Aetrix Electronics and suitable for engine control units, body control modules, and commercial vehicle ABS systems requiring stable component supply with automotive-grade traceability and lifecycle assurance.
Supply support for FMMT494QTA 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 components for automotive, industrial, and computing markets.
The FMMT494QTA belongs to Diodes' AEC-Q101-qualified medium-power transistor product line, engineered specifically for automotive power interface and load-switching applications demanding voltage robustness and thermal stability.
FAQ
Is FMMT494QTA suitable for 24V commercial vehicle applications?
Yes. Its 120V VCEO, 140V VCBO, and AEC-Q101 qualification make it suitable for 24V systems subject to ISO 7637-2 load-dump transients up to ±120V. The device maintains safe operation at TJ = 150°C, supporting under-hood placement near engines or alternators.
What is the recommended PCB layout for thermal performance?
Mount FMMT494QTA on a 15mm × 15mm FR4 pad with ≥1 oz copper coverage on the collector pad. Use thermal vias under the collector pad to inner-layer copper planes. Avoid narrow traces on collector/base; keep emitter path low-inductance to minimize switching overshoot.
Does FMMT494QTA require a base resistor? If so, how is it calculated?
Yes. For IC = 1A and hFE = 20, minimum IB = 50mA. With VBE(sat) ≈ 1.1V and 5V drive, RB = (5V − 1.1V)/50mA = 78Ω. Use 68Ω standard value with 125mW rating to ensure saturation and avoid thermal runaway.
Can FMMT494QTA replace older FMMT494 variants in existing designs?
Yes-FMMT494QTA is a direct replacement for legacy FMMT494 versions with identical pinout, electrical specs, and SOT23 (DN) package. It adds AEC-Q101 qualification and "Green" compliance, requiring no layout or schematic changes in validated automotive designs.
FMMT494QTA 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):
- 120 V
- Vce Saturation (Max) @ Ib, Ic:
- 300mV @ 50mA, 500mA
- Current - Collector Cutoff (Max):
- 100nA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 250mA, 10V
- Power - Max:
- 500 mW
- Frequency - Transition:
- 100MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
FMMT494QTA FAQ
1.How can I place an order for FMMT494QTA through Aetrix?
Please submit a Request for Quotation (RFQ) for FMMT494QTA 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 FMMT494QTA reliable?
The price and inventory of FMMT494QTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT494QTA is usually 5 days.
3.What payment methods are accepted for FMMT494QTA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT494QTA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FMMT494QTA?
FMMT494QTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FMMT494QTA 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 FMMT494QTA?
For technical support, including FMMT494QTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT494QTA requirements.
6.How does Aetrix verify that FMMT494QTA is sourced from the original manufacturer or authorized distributors?
All FMMT494QTA 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 FMMT494QTA meets industry standards.
7.What is the process for return or replacement of FMMT494QTA?
All FMMT494QTA units undergo pre-shipment inspection (PSI). If there is an issue with FMMT494QTA, 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 FMMT494QTA part is unused and in its original packaging.
Return procedure for FMMT494QTA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
FMMT494QTA Tags
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