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Diodes Incorporated FMMT491AQTA
- Part No.:
- FMMT491AQTA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
FMMT491AQTA.pdf
- Description:
- TRANS NPN 40V 1A SOT-23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,650
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Product details
Overview
FMMT491AQTA from Diodes Incorporated is an AEC-Q101-qualified 40V NPN silicon planar medium-power transistor in SOT23 package, delivering 1A continuous collector current, 2A peak pulse current, and 500mW power dissipation with VCE(sat) ≤ 0.5V at IC = 1A/ IB = 100mA. It serves as a robust switching element in automotive load control, DC-DC converter active clamping, and industrial relay drivers.
For engineers reviewing the FMMT491AQTA datasheet, FMMT491AQTA pinout, FMMT491AQTA application, or FMMT491AQTA equivalent, key selection criteria include its AEC-Q101 qualification, low RCE(sat) of 195mΩ, hFE ≥ 200 at 1A, 7V VEBO, and thermal resistance RθJA = 250°C/W on standard FR4 PCB.
Technical Context
This NPN bipolar junction transistor operates in linear or saturated switching mode with guaranteed BVCEO ≥ 40V and VEBO ≥ 7V, enabling use in 24V automotive supply rails and industrial 36V systems. Its fT = 150MHz supports high-speed switching up to ~100kHz with minimal storage time.
The device features fully characterized hFE across 1mA–2A (300–35), ensuring predictable gain in both small-signal amplification and high-current saturation. Its 8kV HBM ESD rating and halogen/antimony-free "Green" construction meet stringent automotive reliability and environmental requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 40V - Withstands 40V collector-emitter voltage before breakdown; suitable for 24V automotive and 36V industrial bus switching. |
| IC (continuous) | 1A - Supports sustained load currents up to 1A without derating at 25°C ambient on standard PCB. |
| VCE(sat) | ≤0.5V @ IC=1A/IB=100mA - Enables <0.5W conduction loss at full rated current, minimizing thermal stress. |
| hFE | ≥200 @ IC=1A - Ensures reliable base drive margin for low-side switch applications with moderate gate/base driver capability. |
| PD | 500mW - Maximum steady-state power dissipation on 15×15mm FR4 with 1oz copper; requires thermal layout consideration above 300mW. |
| RθJA | 250°C/W - Junction-to-ambient thermal resistance defines temperature rise per watt; limits usable power in still-air environments. |
| fT | 150MHz - Transition frequency confirms suitability for fast-switching applications including PWM control and snubber circuits. |
Pinout & Package
SOT23 (Type DN) surface-mount plastic package with matte tin-plated leads, moisture sensitivity level 1, and approximate weight of 0.008g. UL 94V-0 rated molding compound ensures flame resistance in automotive and industrial assemblies.
| 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 support low-impedance return routing. |
| 2 (Base) | Control input | Receives current-limited drive signal; requires ≥100mA for full saturation at 1A collector current. |
| 3 (Collector) | Current source terminal | Switches positive rail or inductive load; thermally coupled to PCB copper for heat dissipation via lead. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive underhood operation (-40°C to +150°C) with PPAP documentation support. |
| Low VCE(sat) | ≤0.5V at 1A enables >95% efficiency in low-voltage switching paths with minimal self-heating. |
| High hFE hold-up | hFE ≥ 35 at 2A ensures stable gain during transient overloads and pulse-width modulated loads. |
| ESD robustness | 8kV HBM rating eliminates need for external protection in typical board-level handling and assembly. |
| Halogen/antimony-free | Meets automotive "Green" standards (<900ppm Br/Cl, <1000ppm Sb), supporting end-of-life recycling compliance. |
Applications
| Automotive Body Control Module | Industrial Solenoid Driver |
|---|---|
Use Scenario: Driving 12V/24V door lock actuators, mirror heaters, or HVAC dampers in BCM subsystems. IC Role / Device Role / Timing Role: Low-side NPN switch controlling ground path of resistive/inductive loads. Use Value: AEC-Q101 qualification and 40V VCEO ensure reliable operation during load dump transients up to 40V. | Use Scenario: Switching 24V solenoids in programmable logic controller (PLC) output modules. IC Role / Device Role / Timing Role: Medium-power interface between microcontroller GPIO and inductive load. Use Value: 1A continuous current and 2A pulse rating accommodate solenoid inrush without external current limiting. |
| DC-DC Converter Active Clamp | LED String Current Sink |
Use Scenario: Clamping voltage spikes in flyback or forward converter secondary-side snubbers. IC Role / Device Role / Timing Role: Fast-switching clamp transistor absorbing leakage energy during MOSFET turn-off. Use Value: 150MHz fT and low storage time enable sub-100ns switching, reducing clamp losses. | Use Scenario: Constant-current sink for multi-segment automotive LED lighting arrays. IC Role / Device Role / Timing Role: Linear or PWM-controlled current regulator in LED tail-light or DRL circuits. Use Value: Tight hFE distribution and low VCE(sat) ensure stable current regulation across temperature. |
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 |
|---|---|---|---|
| ZXTN2010Z | Higher VCEO = 60V; lower hFE = 100 min @ 1A; SOT23-3L package identical. | Preferred where higher voltage margin is required; less suitable for low-base-drive designs. | Select when operating beyond 40V or needing extended safe operating area at elevated VCE. |
| MMBT4401 | Lower VCEO = 40V same; IC = 600mA only; hFE = 100 min @ 150mA - not rated at 1A. | Not recommended for 1A continuous loads; limited to <500mA sustained operation. | Use only in legacy designs with reduced current requirements or where cost is primary constraint. |
Compared with ZXTN2010Z and MMBT4401, FMMT491AQTA uniquely balances 1A continuous rating, AEC-Q101 qualification, and 40V VCEO in a single SOT23 footprint-making it optimal for automotive-grade medium-power switching where reliability and current capacity are jointly critical.
Availability
FMMT491AQTA is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC outputs, DC-DC converter clamps, and LED current regulation requiring stable component supply across production lifecycles.
Supply support for FMMT491AQTA 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 FMMT491AQTA belongs to Diodes' AEC-Q101-qualified medium-power transistor family, engineered specifically for robust switching in harsh-environment automotive and industrial control applications.
FAQ
What is the maximum allowable junction temperature for FMMT491AQTA?
The FMMT491AQTA has an operating junction temperature range of –55°C to +150°C. Its absolute maximum TJ is +150°C, and thermal design must ensure this limit is not exceeded under worst-case power dissipation and ambient conditions, especially when operating near 1A continuous current on standard PCB layouts.
Is FMMT491AQTA pin-compatible with standard SOT23 NPN transistors like MMBT4401?
Yes - FMMT491AQTA uses the standard SOT23 (Type DN) package with emitter-base-collector pinout (1-2-3), matching MMBT4401, ZXTN2010Z, and other industry-standard SOT23 NPN transistors. However, electrical ratings differ significantly, so functional substitution requires verification of VCEO, IC, and hFE requirements.
Does FMMT491AQTA require external base current limiting in microcontroller-driven applications?
Yes - with hFE ≥ 200 at 1A, the device requires ≥5mA base current for full saturation. Most MCU GPIOs cannot safely source 100mA (needed for 1A IC); therefore, a series base resistor or dedicated driver stage is mandatory to avoid MCU damage and ensure reliable switching.
How does the AEC-Q101 qualification impact FMMT491AQTA's use in non-automotive applications?
AEC-Q101 qualification ensures enhanced reliability, including extended temperature cycling, high-temperature operating life, and robust ESD performance. These attributes directly benefit industrial, medical, and aerospace applications where long-term stability and field failure avoidance are critical-even outside automotive contexts.
FMMT491AQTA 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):
- 40 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 100mA, 1A
- Current - Collector Cutoff (Max):
- 100nA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 300 @ 500mA, 5V
- Power - Max:
- 500 mW
- Frequency - Transition:
- 150MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
FMMT491AQTA FAQ
1.How can I place an order for FMMT491AQTA through Aetrix?
Please submit a Request for Quotation (RFQ) for FMMT491AQTA 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 FMMT491AQTA reliable?
The price and inventory of FMMT491AQTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT491AQTA is usually 5 days.
3.What payment methods are accepted for FMMT491AQTA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT491AQTA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FMMT491AQTA?
FMMT491AQTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FMMT491AQTA 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 FMMT491AQTA?
For technical support, including FMMT491AQTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT491AQTA requirements.
6.How does Aetrix verify that FMMT491AQTA is sourced from the original manufacturer or authorized distributors?
All FMMT491AQTA 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 FMMT491AQTA meets industry standards.
7.What is the process for return or replacement of FMMT491AQTA?
All FMMT491AQTA units undergo pre-shipment inspection (PSI). If there is an issue with FMMT491AQTA, 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 FMMT491AQTA part is unused and in its original packaging.
Return procedure for FMMT491AQTA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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