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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi 2N6491

Name: 2N6491
Brand: onsemi
SKU: 2N6491
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N6491

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: 2N6491.pdf

Description:: TRANS PNP 80V 15A TO-220

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Product details

Overview

2N6491 from onsemi is a PNP silicon power transistor in TO-220 package, rated for 80 V_CEO, 15 A continuous collector current, and 75 W power dissipation at T_C = 25°C. It delivers DC current gain (h_FE) ≥5.0 at 15 A and supports switching and linear amplifier applications in industrial motor controls and power supplies.

For engineers reviewing the 2N6491 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO = 80 V, I_C = 15 A, R_JC = 1.67 °C/W, f_T = 5.0 MHz, and TO-220 thermal performance under forced-air or heatsink-mounted conditions.

Technical Context

The 2N6491 operates as a medium-power PNP bipolar junction transistor with complementary pairing to NPN devices 2N6487/2N6488. Its safe operating area (SOA) is second-breakdown limited up to 5 ms pulses and thermally limited at case temperatures above 25°C, with derating slope of 0.6 W/°C.

Electrical behavior is characterized by V_CE(sat) ≤ 3.5 V at I_C = 15 A / I_B = 5.0 A, V_BE(on) ≤ 3.5 V under same conditions, and C_ob ≈ 700 pF at V_CB = 10 V - parameters critical for snubber design and switching loss estimation in hard-switched topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 Vdc - Maximum collector-emitter voltage before breakdown under open-base condition; defines upper rail limit in high-side switch designs.
I_C Continuous	15 Adc - Sustained collector current capability with adequate heatsinking; sets minimum heatsink requirement for 75 W conduction loss.
P_D @ T_C = 25°C	75 W - Total power dissipation limit at case temperature 25°C; requires thermal interface and heatsink design targeting R_JA ≤ 70 °C/W.
h_FE @ I_C = 15 A	≥5.0 - Minimum DC current gain at full rated current; determines required base drive current (I_B ≥ 3 A) for saturation.
f_T	5.0 MHz - Current-gain bandwidth product at I_C = 1.0 A; indicates usable frequency range for small-signal amplification or moderate-speed switching.
R_JC	1.67 °C/W - Junction-to-case thermal resistance; enables calculation of junction temperature rise ΔT_J = P_D × 1.67 for reliability margining.

Pinout & Package

2N6491 uses TO-220 package (Case 221A, Style 1), with metal tab electrically connected to collector. The plastic body provides electrical isolation between collector and mounting surface when insulated hardware is used.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal; requires ≥3 A DC base current to saturate at I_C = 15 A per h_FE min spec.
2 & 4	Collector	Main high-current path; pins 2 and 4 are internally bonded to collector; metal tab is also collector - must be isolated or grounded per circuit function.
3	Emitter	Current return path; common reference for base drive and load connection in high-side switch configurations.

Key Features

Feature	Design Value
High DC current gain	h_FE ≥20 at I_C = 5.0 A - reduces base drive power and simplifies driver stage design in linear regulators.
High f_T	5.0 MHz - supports audio-frequency amplification and PWM switching up to ~500 kHz with acceptable gain roll-off.
TO-220 compact package	Standardized footprint with 2.54 mm pin pitch - enables drop-in replacement in legacy PCBs designed for TO-220 power transistors.
Pb-free & RoHS compliant	G-suffix marking - meets environmental compliance requirements for industrial and consumer end equipment without lead content.

Applications

Industrial Motor Control	DC Power Supply Regulation
Use Scenario: High-side switching in 24–48 V brushed DC motor H-bridge drivers. IC Role / Device Role / Timing Role: PNP power switch controlling motor voltage rail; operates in saturation during ON state and cutoff during OFF state. Use Value: 80 V_CEO rating accommodates back-EMF spikes; 15 A current supports motors up to ~700 W mechanical output with appropriate heatsinking.	Use Scenario: Series pass element in linear regulated DC power supplies delivering up to 12 V @ 10 A. IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output via base bias; dissipates heat proportional to (V_IN − V_OUT) × I_LOAD. Use Value: 75 W power rating allows operation at 10 A with 7.5 V dropout; R_JC = 1.67 °C/W enables predictable thermal design using standard TO-220 heatsinks.
AC-DC SMPS Auxiliary Supply	Overcurrent Protection Circuit
Use Scenario: Discrete transistor in auxiliary bias winding rectifier stage of off-line flyback converters. IC Role / Device Role / Timing Role: Synchronous rectifier or linear regulator for control IC bias supply; handles peak currents during startup surge. Use Value: V_CEO = 80 V withstands reflected flyback voltage spikes; low V_CE(sat) minimizes conduction loss in low-voltage bias rails.	Use Scenario: Current-limiting switch in battery protection or lab power supply foldback circuits. IC Role / Device Role / Timing Role: Fast-acting crowbar or shutdown switch triggered by comparator output during overcurrent fault. Use Value: 5.0 MHz f_T ensures sub-microsecond turn-off response; SOA curves validate reliable operation under short-circuit pulse stress up to 5 ms.

Industrial Motor Control

DC Power Supply Regulation

Use Scenario: High-side switching in 24–48 V brushed DC motor H-bridge drivers.

IC Role / Device Role / Timing Role: PNP power switch controlling motor voltage rail; operates in saturation during ON state and cutoff during OFF state.

Use Value: 80 V_CEO rating accommodates back-EMF spikes; 15 A current supports motors up to ~700 W mechanical output with appropriate heatsinking.

Use Scenario: Series pass element in linear regulated DC power supplies delivering up to 12 V @ 10 A.

IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output via base bias; dissipates heat proportional to (V_IN − V_OUT) × I_LOAD.

Use Value: 75 W power rating allows operation at 10 A with 7.5 V dropout; R_JC = 1.67 °C/W enables predictable thermal design using standard TO-220 heatsinks.

AC-DC SMPS Auxiliary Supply

Overcurrent Protection Circuit

Use Scenario: Discrete transistor in auxiliary bias winding rectifier stage of off-line flyback converters.

IC Role / Device Role / Timing Role: Synchronous rectifier or linear regulator for control IC bias supply; handles peak currents during startup surge.

Use Value: V_CEO = 80 V withstands reflected flyback voltage spikes; low V_CE(sat) minimizes conduction loss in low-voltage bias rails.

Use Scenario: Current-limiting switch in battery protection or lab power supply foldback circuits.

IC Role / Device Role / Timing Role: Fast-acting crowbar or shutdown switch triggered by comparator output during overcurrent fault.

Use Value: 5.0 MHz f_T ensures sub-microsecond turn-off response; SOA curves validate reliable operation under short-circuit pulse stress up to 5 ms.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11G	Higher V_CEO = 100 V, lower I_C = 8 A, TO-252 (DPAK) package	Surface-mount alternative with reduced current handling but better board-level thermal management in compact layouts	Select when space-constrained PCBs require SMT assembly and max V_CEO > 80 V is needed; not pin-compatible with 2N6491.
BD711	V_CEO = 80 V, I_C = 12 A, TO-126 package, h_FE min = 25 at 2 A	Lower power rating (40 W), smaller package, higher gain at low current - suited for driver stages rather than main power switching	Choose for pre-driver or medium-power linear regulation where 15 A capability is unnecessary and TO-126 footprint is preferred.

Compared with MJD44H11G and BD711, the 2N6491 offers the highest continuous current (15 A) and power dissipation (75 W) in through-hole TO-220, making it optimal for high-reliability industrial switching where thermal mass and serviceability matter.

Availability

2N6491 is available at Aetrix Electronics and suitable for industrial motor control, DC power supply regulation, and AC-DC SMPS auxiliary supply applications requiring stable component supply and long-term manufacturing continuity.

Supply support for 2N6491 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

onsemi is a global semiconductor supplier focused on energy-efficient electronics, delivering discrete, analog, logic, and custom devices for automotive, industrial, cloud, and IoT markets.

The 2N6491 belongs to onsemi's complementary silicon power transistor family, engineered for robust general-purpose amplifier and switching use in industrial power systems where reliability, thermal stability, and JEDEC-standard packaging are essential.

FAQ

What is the maximum collector-emitter voltage rating for the 2N6491?

The 2N6491 has a maximum collector-emitter voltage (V_CEO) rating of 80 Vdc under open-base conditions. This value is confirmed in the "Maximum Ratings" table of the official onsemi datasheet (Rev. 17, October 2024) and applies specifically to the 2N6491 variant - distinct from the 2N6490's 60 V rating. Exceeding this voltage risks avalanche breakdown and permanent device failure.

Does the 2N6491 have a built-in heatsink tab connection?

Yes, the metal tab on the 2N6491 TO-220 package is electrically connected to the collector terminal (pins 2 and 4). This direct thermal and electrical path enables efficient heat transfer to an external heatsink but requires electrical isolation (e.g., mica washer + nylon screw) if the heatsink is grounded or at a different potential than the collector node in the circuit.

What is the minimum DC current gain (h_FE) of the 2N6491 at full rated current?

The 2N6491 guarantees a minimum DC current gain (h_FE) of 5.0 when operated at I_C = 15 A and V_CE = 4.0 Vdc, as specified in the "ELECTRICAL CHARACTERISTICS" table. This defines the worst-case base drive requirement: I_B ≥ 3.0 A to ensure saturation under full load, critical for low-loss switching applications.

Is the 2N6491 RoHS compliant and lead-free?

Yes, the 2N6491 is RoHS compliant and lead-free, indicated by the "G" suffix in its ordering code (e.g., 2N6491G) and explicitly stated in the "Features" section of the onsemi datasheet. The device meets EU Directive 2011/65/EU and is suitable for environmentally regulated industrial and consumer end equipment.

How does the 2N6491 differ from the 2N6490 in terms of voltage rating?

The 2N6491 is rated for V_CEO = 80 Vdc, while the 2N6490 is rated for V_CEO = 60 Vdc - a 20 V difference confirmed in both the "Maximum Ratings" and "ELECTRICAL CHARACTERISTICS" sections of the shared datasheet. This distinction is tied to process and wafer-level binning; the two parts are not interchangeable without verifying circuit voltage margins against the 2N6491's higher rating.

2N6491 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 15 A

Voltage - Collector Emitter Breakdown (Max):: 80 V

Vce Saturation (Max) @ Ib, Ic:: 3.5V @ 5A, 15A

Current - Collector Cutoff (Max):: 1mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 20 @ 5A, 4V

Power - Max:: 1.8 W

Frequency - Transition:: 5MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

2N6491 FAQ

1.How can I place an order for 2N6491 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N6491 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 2N6491 reliable?

The price and inventory of 2N6491 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N6491 is usually 5 days.

3.What payment methods are accepted for 2N6491?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N6491 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N6491?

2N6491 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N6491 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 2N6491?

For technical support, including 2N6491 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N6491 requirements.

6.How does Aetrix verify that 2N6491 is sourced from the original manufacturer or authorized distributors?

All 2N6491 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 2N6491 meets industry standards.

7.What is the process for return or replacement of 2N6491?

All 2N6491 units undergo pre-shipment inspection (PSI). If there is an issue with 2N6491, 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 2N6491 part is unused and in its original packaging.

Return procedure for 2N6491:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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