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Diodes Incorporated FMMT491AQTC
- Part No.:
- FMMT491AQTC
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
FMMT491AQTC.pdf
- Description:
- TRANS NPN 40V 1A SOT-23-3
- Quantity:
- Payment:
- Shipping:
Inventory:6,904
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Product details
Overview
FMMT491AQTC 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 195mΩ RCE(sat), used for automotive load switching and power control in engine management modules.
For engineers reviewing the FMMT491AQTC datasheet, FMMT491AQTC pinout, FMMT491AQTC application, or FMMT491AQTC equivalent, key selection criteria include VCEO = 40V, IC = 1A, hFE ≥ 200 at 1A, RθJA = 250°C/W, and AEC-Q101 qualification for under-hood automotive use.
Technical Context
This NPN bipolar junction transistor operates as a medium-power switch with low saturation voltage (VCE(sat) ≤ 0.5V at IC = 1A, IB = 100mA) and high DC current gain (hFE ≥ 35 at IC = 2A), enabling efficient on-state conduction in 12V automotive systems.
It features robust thermal performance (RθJA = 250°C/W on 15mm × 15mm FR4 with 1 oz copper) and high reliability (ESD HBM ≥ 8kV, operating range –55°C to +150°C), meeting stringent automotive environmental requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 40 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration |
| IC (continuous) | 1 A - Sustained collector current capability without thermal runaway on standard PCB layout |
| RCE(sat) | 195 mΩ - Equivalent on-resistance determining conduction loss and self-heating at rated current |
| hFE | ≥200 @ IC=1A - Ensures sufficient base drive margin for reliable saturation in high-current switching |
| PD | 500 mW - Maximum steady-state power dissipation at 25°C ambient with specified PCB copper area |
| fT | 150 MHz - Transition frequency indicating usable bandwidth for moderate-speed switching (≤100 kHz PWM) |
Pinout & Package
Package: SOT23 (Type DN), surface-mount plastic case with matte tin-plated leads, moisture sensitivity level 1 per J-STD-020, weight ≈ 0.008 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | E | Current return path; connected to ground or low-side reference in common-emitter switch topology |
| 2 (Base) | B | Control input requiring ~100 mA drive for full saturation at 1 A collector current |
| 3 (Collector) | C | High-side load connection point; carries full switched current and dissipates majority of power |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood applications including engine control units and body electronics |
| Low RCE(sat) | 195 mΩ enables <0.5 W conduction loss at 1 A, reducing heatsink requirement in space-constrained modules |
| High ESD immunity | HBM ≥ 8 kV supports robust handling and assembly in automotive manufacturing environments |
| Green, lead-free construction | Halogen- and antimony-free molding compound compliant with RoHS 3 and automotive environmental standards |
Applications
| Engine Control Unit (ECU) Solenoid Drive | Automotive HVAC Blower Motor Control |
|---|---|
Use Scenario: Driving 12V fuel injector solenoids with 50–100ms pulse width in gasoline direct injection systems. IC Role / Device Role / Timing Role: NPN medium-power switch providing precise on/off control with fast turn-on/turn-off response. Use Value: VCEO = 40V withstands load dump transients; RCE(sat) ≤ 0.5V minimizes coil heating during extended duty cycles. | Use Scenario: Controlling brushed DC blower motor speed via PWM in climate control modules. IC Role / Device Role / Timing Role: Low-side switching element handling up to 1A continuous current with thermal stability. Use Value: hFE ≥ 200 at 1A ensures stable base drive across temperature; TJ max = +150°C supports under-dash mounting. |
| Body Control Module (BCM) Relay Driver | LED Headlamp Dimming Circuit |
Use Scenario: Replacing mechanical relays for door lock actuators and window lift motors in BCM designs. IC Role / Device Role / Timing Role: Solid-state replacement for electromechanical relay, driven by microcontroller GPIO. Use Value: ICM = 2A handles inrush current of 12V solenoids; AEC-Q101 qualification ensures field reliability. | Use Scenario: Current-regulated dimming of high-brightness LED arrays in adaptive front lighting systems. IC Role / Device Role / Timing Role: Linear or PWM-controlled current sink for analog/digital brightness adjustment. Use Value: VBE(sat) ≤ 1.1V at 1A enables accurate current sensing; low Cobo = 10pF supports clean PWM edges. |
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 |
|---|---|---|---|
| ZXTN25050DFHTA | VCEO = 50V, IC = 1.5A, SOT23 package, but hFE min = 100 @ 1A (lower gain) | Higher voltage margin but reduced current gain stability at 1A | Preferred where higher VCEO is critical and base drive headroom is ample |
| MMBT4401-7-F | VCEO = 40V, IC = 600mA, SOT23, hFE ≥ 100 @ 150mA (not rated at 1A) | Lower continuous current rating limits use to sub-600mA loads | Suitable only for light-duty signal switching, not 1A automotive loads |
Compared with ZXTN25050DFHTA and MMBT4401-7-F, FMMT491AQTC uniquely combines 40V/1A rating, AEC-Q101 qualification, and hFE ≥ 200 at full 1A-making it the only option validated for sustained 1A automotive switching with minimal base drive overhead.
Availability
FMMT491AQTC is available at Aetrix Electronics and suitable for automotive engine control, body electronics, and HVAC subsystems requiring stable component supply with AEC-Q101 compliance and traceable sourcing.
Supply support for FMMT491AQTC 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 and manufacturing operations across Asia and the Americas.
FMMT491AQTC belongs to Diodes' AEC-Q101-qualified medium-power transistor product line, engineered specifically for automotive load switching where reliability, thermal stability, and transient tolerance are essential.
FAQ
What is the maximum allowable collector current for continuous operation?
The FMMT491AQTC supports 1 A continuous collector current (IC) when mounted on a 15 mm × 15 mm FR4 PCB with 1 oz copper, at TA = +25°C. Derating is required above 25°C ambient, with full derating to zero at +150°C junction temperature per the published thermal curve.
Is FMMT491AQTC pin-compatible with standard SOT23 NPN transistors like MMBT2222A?
No-FMMT491AQTC uses the SOT23 (Type DN) pinout (Emitter-Base-Collector on pins 1-2-3), whereas MMBT2222A follows the SOT23 (Type DA) pinout (Emitter-Collector-Base). Physical insertion into the same footprint will result in incorrect circuit connection and potential damage.
Does FMMT491AQTC support PWM switching at frequencies above 20 kHz?
Yes-its fT = 150 MHz and low output capacitance (Cobo = 10 pF) support clean switching up to at least 100 kHz. However, practical PWM efficiency depends on external base drive strength and layout; VCE(sat) remains stable under pulsed conditions up to 2A with ≤2% duty cycle.
What does the "Q" in FMMT491AQTC signify?
The "Q" denotes Diodes Incorporated's automotive-grade product family, indicating full AEC-Q101 qualification, PPAP capability, and green (halogen/antimony-free) construction. It distinguishes this variant from industrial-grade FMMT491ATA/FMMT491ATC, which share identical electrical specs but lack automotive certification documentation.
FMMT491AQTC 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
FMMT491AQTC FAQ
1.How can I place an order for FMMT491AQTC through Aetrix?
Please submit a Request for Quotation (RFQ) for FMMT491AQTC 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 FMMT491AQTC reliable?
The price and inventory of FMMT491AQTC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT491AQTC is usually 5 days.
3.What payment methods are accepted for FMMT491AQTC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT491AQTC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FMMT491AQTC?
FMMT491AQTC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FMMT491AQTC 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 FMMT491AQTC?
For technical support, including FMMT491AQTC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT491AQTC requirements.
6.How does Aetrix verify that FMMT491AQTC is sourced from the original manufacturer or authorized distributors?
All FMMT491AQTC 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 FMMT491AQTC meets industry standards.
7.What is the process for return or replacement of FMMT491AQTC?
All FMMT491AQTC units undergo pre-shipment inspection (PSI). If there is an issue with FMMT491AQTC, 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 FMMT491AQTC part is unused and in its original packaging.
Return procedure for FMMT491AQTC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
FMMT491AQTC Tags
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