FMMT634TA Diodes Inc. Transistor Darlington Pair (SOT23 (3-Pin)) In Stock
Diodes Inc. FMMT634TA is an NPN Darlington transistor in a compact SOT-23 3-pin package with 100 V collector-emitter voltage, 0.9 A collector current, and an extremely high DC current gain of 15000 minimum. It targets low-power switching, relay driving, and signal amplification applications requiring ultra-high current gain from a small surface mount device.
- Manufacturer
- Diodes Inc.
- Package
- SOT23 (3-Pin)
- Pin Count
- 3
- Lifecycle
- ACTIVE
- Datasheet
- FMMT634TA Datasheet PDF
- Category
- Transistor Darlington Pair
- Price
- From $0.2600(MOQ 50)
- Temp Range
- ?°C to 150.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Ultra-high DC current gain (hFE) minimum of 15000 enables microcontroller I/O pins to directly drive relay coils and LED arrays
- 100 V collector-emitter breakdown voltage (VCEO) supports switching in higher-voltage industrial and automotive-adjacent circuits
- 0.9 A maximum collector current handles small motor inrush and relay switching loads from a tiny SOT-23 footprint
- NPN Darlington configuration in SOT-23 saves board space vs. discrete two-transistor alternatives while achieving equivalent gain
Applications
The FMMT634TA is used to interface low-current microcontroller outputs with relay coils, solenoids, and LED driver stages in industrial automation and consumer electronics. Its 15000 minimum hFE allows a single 1 mA base drive to switch up to 0.9 A collector loads, making it ideal for battery-powered IoT sensors where driving power must be minimized. The SOT-23 package suits compact motor control boards, home automation modules, and wearable device actuator drivers requiring a high-gain NPN Darlington in a minimal footprint.
Specifications
| Pbfree Code | Yes |
| Factory Lead Time | 12Weeks |
| YTEOL | 7 |
| Collector Current-Max (IC) | 0.9A |
| Collector-Emitter Voltage-Max | 100V |
| Configuration | DARLINGTON |
| DC Current Gain-Min (hFE) | 15000 |
| JESD-30 Code | R-PDSO-G3 |
| JESD-609 Code | e3 |
| Number of Elements | 1 |
| Package Body Material | PLASTIC/EPOXY |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Peak Reflow Temperature (Cel) | 260 |
| Polarity/Channel Type | NPN |
| Power Dissipation-Max (Abs) | 0.806W |
| Qualification Status | Not Qualified |
| Surface Mount | YES |
| Terminal Finish | MATTE TIN |
| Terminal Form | GULL WING |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Transistor Element Material | SILICON |
| Package | SOT23 (3-Pin) |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| Country of Origin | Mainland China |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How does the FMMT634TA's 15000 minimum hFE benefit microcontroller-to-relay interface designs?
With a minimum DC current gain of 15000, the FMMT634TA allows a microcontroller GPIO pin sourcing as little as 0.1 mA to drive a relay coil requiring 1 A; this eliminates the need for a driver IC or discrete Darlington pair in 3.3 V or 5 V logic systems, simplifying the schematic and reducing BOM cost for relay-heavy automation controllers.
Can the FMMT634TA switch inductive loads on 48 V DC relay coils given its 100 V VCEO rating?
Yes, the FMMT634TA's 100 V collector-emitter breakdown voltage safely handles 48 V DC coils with inductive flyback spikes; a flyback diode across the coil is still required to clamp the spike below 100 V, and the 0.9 A collector current rating must not be exceeded continuously to keep junction temperature within the SOT-23 package's thermal limits.
When would an engineer select the FMMT634TA over a single NPN BJT such as the 2N3904 for a sensor output stage?
An engineer selects the FMMT634TA when the load current exceeds the base drive capability of a single NPN like the 2N3904 (hFE typically 100-300); the FMMT634TA's 15000 hFE Darlington stage drives 0.9 A loads from under 100 µA base current, while the 2N3904 would require 3 mA to 9 mA base current for the same load, making the Darlington a better choice for energy-constrained IoT and wearable applications.
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About Diodes Inc.
Diodes Inc. is a leading electronic component manufacturer. FindMyChip sources Diodes Inc. ICs directly from authorized China distributors, offering competitive pricing and reliable stock.
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Diode
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 50+ | $0.5430 | $27.15 |
| 100+ | $0.4412 | $44.12 |
| 250+ | $0.4120 | $103.00 |
| 500+ | $0.3403 | $170.16 |
| 1000+ | $0.3078 | $307.81 |
| 3000+ | $0.2600 | $780.00 |
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