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onsemi MJE800STU
- Part No.:
- MJE800STU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
MJE800STU.pdf
- Description:
- TRANS NPN DARL 60V 4A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,343
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Product details
Overview
MJE800STU from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon Darlington transistor in TO-126 package, rated for 60 V VCEO, 4 A IC, and 40 W PC at TC = 25°C, with integrated base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ), used in high-gain linear and switching applications such as relay drivers and power supply control circuits.
For engineers reviewing the MJE800STU datasheet, pinout, applications, or equivalent options, key selection criteria include verified DC current gain (hFE ≥ 750 @ IC = 1.5 A), collector-emitter saturation voltage (VCE(sat) ≤ 2.5 V), built-in bias resistors, thermal derating behavior, and TO-126 mechanical compatibility with heatsink mounting.
Technical Context
The MJE800STU implements a monolithic Darlington pair with integrated base-emitter resistors to simplify external biasing and improve turn-off speed. Its structure delivers high DC current gain while maintaining low leakage (ICEO ≤ 100 µA at VCE = 60 V, TC = 25°C) and stable junction temperature operation up to 150°C.
Designed for medium-power linear and switching roles, it supports continuous collector currents up to 4 A with VCE(sat) specified at multiple operating points (e.g., 2.5 V @ IC = 1.5 A, IB = 30 mA), and exhibits safe operating area (SOA) compliance per Figure 5 of the original datasheet under DC and pulsed conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 60 V - Maximum allowable collector-emitter voltage before breakdown under open-base condition. |
| IC | 4 A - Continuous DC collector current rating at TC = 25°C; derates linearly above 25°C case temperature. |
| PC | 40 W - Maximum power dissipation at TC = 25°C; requires heatsinking for sustained operation near rating. |
| hFE | ≥750 - Minimum DC current gain at VCE = 3 V, IC = 1.5 A; enables low-base-drive switching in driver stages. |
| VCE(sat) | ≤2.5 V - Collector-emitter saturation voltage at IC = 1.5 A, IB = 30 mA; defines conduction loss in on-state switching. |
| R1 / R2 | ≈10 kΩ / ≈0.6 kΩ - Integrated base-emitter resistors reduce external component count and improve turn-off reliability. |
Pinout & Package
Package: TO-126 (3-lead, through-hole, thermally enhanced plastic). Mounting tab is electrically connected to collector. Standard footprint with 16.10 mm × 13.06 mm outline and 3.20 mm mounting hole.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Emitting terminal of Darlington pair | Low-impedance output node; referenced to ground in common-emitter configurations. |
| 2 (Collector) | Collecting terminal; tied to mounting tab | High-current output path; requires electrical isolation from heatsink unless tab is designated as circuit ground. |
| 3 (Base) | Control input node | Driven through internal R1/R2 network; accepts TTL/CMOS-compatible logic-level signals without external bias resistors. |
Key Features
| Feature | Design Value |
|---|---|
| Monolithic Darlington construction | Single-die integration eliminates inter-device parameter mismatch and improves thermal tracking between input/output transistors. |
| Built-in base-emitter resistors | R1 ≈ 10 kΩ and R2 ≈ 0.6 kΩ enable direct logic-level drive and reduce external component count by two resistors. |
| High DC current gain | hFE ≥ 750 at IC = 1.5 A ensures robust switching margin with minimal base drive current (e.g., ~2 mA required). |
| Thermal robustness | Junction temperature limit of 150°C and SOA-rated operation support reliable use in industrial ambient environments up to 100°C case temperature. |
Applications
| Relay Driver Circuits | DC Motor Control Stages |
|---|---|
Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and industrial control panels. IC Role / Device Role / Timing Role: High-gain switch amplifying microcontroller GPIO output to energize relay coil with <10 mA base current. Use Value: Eliminates need for discrete base-bias resistors and secondary transistor stage, reducing BOM count and PCB area. | Use Scenario: Controlling bidirectional brushed DC motors in HVAC actuators and automated valves. IC Role / Device Role / Timing Role: Low-side switching element in H-bridge half-bridge sections, handling peak currents up to 4 A. Use Value: Confirmed VCE(sat) ≤ 2.5 V at 1.5 A ensures <3.75 W conduction loss, minimizing heatsink requirements. |
| Linear Power Supply Regulators | Overcurrent Protection Circuits |
Use Scenario: Pass transistor in series-regulated 5–15 V, 2–3 A bench power supplies. IC Role / Device Role / Timing Role: Voltage-controlled current source operating in active region with fixed base bias. Use Value: Stable hFE ≥ 750 and low VBE(on) (≤2.5 V) support precise current mirroring and thermal compensation design. | Use Scenario: Current-sensing switch in foldback protection for SMPS primary-side controllers. IC Role / Device Role / Timing Role: Fast-turn-off Darlington triggered by sense resistor voltage exceeding threshold. Use Value: Built-in R2 provides controlled base discharge path, reducing turn-off delay vs. standard Darlingtons without resistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN Darlington transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TIP120 | VCEO = 60 V, IC = 5 A, hFE ≥ 1000, TO-220 package; no built-in R2, higher gain but requires external turn-off resistor. | Higher current capability suits larger loads; TO-220 footprint incompatible with TO-126 PCB layout. | Select when higher IC rating and gain are needed and board redesign is acceptable. |
| BD679 | VCEO = 80 V, IC = 4 A, hFE ≥ 750, TO-126 package; no integrated resistors, lower VBE(on) (~1.5 V). | Higher voltage rating enables 48 V systems; external biasing required increases component count and layout complexity. | Select when operating above 60 V or when discrete bias control is preferred for dynamic response tuning. |
Compared with TIP120 and BD679, the MJE800STU uniquely combines TO-126 mechanical compatibility, integrated R1/R2 network, and guaranteed hFE ≥ 750 at 1.5 A-making it optimal for space-constrained, low-component-count relay and motor driver designs where 60 V rating suffices.
Availability
MJE800STU is available at Aetrix Electronics and suitable for relay driver circuits, DC motor control stages, and linear power supply regulators requiring stable component supply, long-term industrial availability, and consistent parametric performance across production lots.
Supply support for MJE800STU 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
ON Semiconductor is a global semiconductor supplier delivering energy-efficient, scalable solutions for automotive, industrial, cloud, medical, and IoT applications.
The MJE800STU belongs to Fairchild's legacy bipolar power transistor family, designed specifically for cost-sensitive, medium-power linear and switching applications where high DC gain and simplified biasing are critical.
FAQ
What is the maximum collector-emitter voltage rating for the MJE800STU?
The MJE800STU has a maximum collector-emitter voltage (VCEO) rating of 60 V at TC = 25°C. This rating applies under open-base conditions and must be derated at elevated case temperatures per the datasheet's power derating curve. Exceeding this voltage risks avalanche breakdown and permanent device failure.
Does the MJE800STU include built-in base resistors, and what are their values?
Yes, the MJE800STU integrates two on-die resistors: R1 ≈ 10 kΩ between base and input, and R2 ≈ 0.6 kΩ between base and emitter. These eliminate the need for external bias components in most switching applications and improve turn-off speed by providing a defined discharge path for base charge.
What is the DC current gain (hFE) specification for the MJE800STU, and under what conditions is it guaranteed?
The MJE800STU guarantees hFE ≥ 750 at VCE = 3 V and IC = 1.5 A, with test condition TC = 25°C. This minimum gain is specified for the MJE800 and MJE802 variants and ensures predictable base drive requirements in driver-stage designs.
Can the MJE800STU be used in surface-mount applications?
No-the MJE800STU is packaged exclusively in the through-hole TO-126 format and is not available in surface-mount variants. Its leaded construction and mounting tab require wave soldering or hand-soldering with appropriate thermal relief; SMT alternatives like the NSS12501LT1G are not functionally or pin-compatible replacements.
What is the thermal resistance from junction to case (RθJC) for the MJE800STU?
The MJE800STU has a typical junction-to-case thermal resistance (RθJC) of 0.625°C/W, derived from its 40 W PC rating at TC = 25°C (RθJC = (TJ(max) − TC) / PC = (150 − 25) / 40). This value assumes full metal tab contact with a heatsink and is critical for calculating required heatsink thermal resistance in thermal design.
MJE800STU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- NPN - Darlington
- Current - Collector (Ic) (Max):
- 4 A
- Voltage - Collector Emitter Breakdown (Max):
- 60 V
- Vce Saturation (Max) @ Ib, Ic:
- 2.5V @ 30mA, 1.5A
- Current - Collector Cutoff (Max):
- 100µA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 750 @ 1.5A, 3V
- Power - Max:
- 40 W
- Frequency - Transition:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
MJE800STU FAQ
1.How can I place an order for MJE800STU through Aetrix?
Please submit a Request for Quotation (RFQ) for MJE800STU 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 MJE800STU reliable?
The price and inventory of MJE800STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJE800STU is usually 5 days.
3.What payment methods are accepted for MJE800STU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJE800STU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MJE800STU?
MJE800STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MJE800STU 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 MJE800STU?
For technical support, including MJE800STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJE800STU requirements.
6.How does Aetrix verify that MJE800STU is sourced from the original manufacturer or authorized distributors?
All MJE800STU 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 MJE800STU meets industry standards.
7.What is the process for return or replacement of MJE800STU?
All MJE800STU units undergo pre-shipment inspection (PSI). If there is an issue with MJE800STU, 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 MJE800STU part is unused and in its original packaging.
Return procedure for MJE800STU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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