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

STMicroelectronics BD241C

Name: BD241C
Brand: STMicroelectronics
SKU: BD241C
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD241C

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD241C.pdf

Description:: TRANS NPN 100V 3A TO-220

Quantity:: RFQ Add To RFQ list

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Inventory:2,220

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Product details

Overview

BD241C from STMicroelectronics is a silicon epitaxial-base NPN power transistor in TO-220 package, rated for 100 V V_CEO, 3 A continuous collector current, and 40 W junction-case power dissipation at T_c ≤ 25 °C. It is designed for medium-power linear amplification and switching applications such as audio output stages and DC motor drivers.

For engineers reviewing the BD241C datasheet, BD241C pinout, BD241C application, or BD241C equivalent, key selection criteria include V_CEO = 100 V, I_C = 3 A, h_FE ≥ 10 at I_C = 3 A, V_CE(sat) = 1.2 V, and thermal resistance R_thj-case = 3.13 °C/W - all critical for thermal design and saturation loss in high-current switching circuits.

Technical Context

The BD241C operates as a medium-power bipolar junction transistor with fixed-emitter configuration and base-controlled current amplification. Its 100 V V_CEO rating supports operation in 48 V and 72 V DC bus systems, while its 3 A I_C and 5 A I_CM enable pulsed load handling in relay drivers and PWM-controlled power stages.

Designed for direct mounting to heatsinks via the collector-connected tab, it uses a single-metal-layer emitter structure and epitaxial base for stable h_FE across temperature. The 1.2 V V_CE(sat) at I_C = 3 A / I_B = 0.6 A ensures low conduction loss in Class AB amplifier outputs and half-bridge high-side switches.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	100 V - Maximum safe collector-emitter voltage with base open; defines usable DC bus voltage headroom in switching applications.
I_C	3 A - Continuous collector current limit; sets maximum RMS load current in linear regulators and audio output stages.
P_tot (T_c ≤ 25 °C)	40 W - Junction-to-case power dissipation limit; determines minimum heatsink thermal resistance required for safe operation.
V_CE(sat)	1.2 V @ I_C = 3 A, I_B = 0.6 A - Saturation voltage defining conduction loss and heat generation in switch-mode operation.
h_FE	≥10 @ I_C = 3 A, V_CE = 4 V - Minimum DC current gain ensuring reliable base drive sizing for 3 A loads.
R_thj-case	3.13 °C/W - Thermal resistance from junction to case; used to calculate junction temperature rise under known power dissipation.

Pinout & Package

BD241C is housed in a standard JEDEC TO-220 plastic package with collector-connected metal tab (pin 2), emitter (pin 1), and base (pin 3) arranged left-to-right when viewed from the front (flat side facing viewer, leads down).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for majority carriers	Connected to ground or low-side return; must handle full load current and be routed with low-inductance layout.
2 (Collector)	Current entry path; electrically tied to metal tab	Tab serves as primary thermal interface; must be electrically isolated from heatsink unless system ground reference permits.
3 (Base)	Control terminal for minority carrier injection	Requires current-limited drive (I_B ≤ 1 A); sensitive to ESD and requires series resistor in most driver circuits.

Key Features

Feature	Design Value
High V_CEO rating	100 V enables use in 72 V industrial DC systems without derating or series stacking.
Low V_CE(sat)	1.2 V minimizes conduction loss and self-heating in 3 A switching loads, reducing heatsink size by ~25% vs. higher-saturation alternatives.
TO-220 mechanical standardization	Compatible with widely available mounting hardware, thermal pads, and automated assembly tooling for through-hole PCBs.
Stable h_FE at high I_C	Guaranteed h_FE ≥ 10 at 3 A ensures predictable base drive requirements across production lots and temperature ranges.

Applications

Audio Power Amplifier Output Stage

DC Motor Driver (H-Bridge Low-Side)

Use Scenario: Final output stage of 20 W Class AB audio amplifier driving 4–8 Ω speakers.

IC Role / Device Role / Timing Role: NPN power switch delivering peak current up to 3 A into reactive speaker load.

Use Value: 100 V V_CEO provides margin against flyback transients; 1.2 V V_CE(sat) limits idle-stage heating and improves efficiency above 5 W output.

Use Scenario: Low-side switch in 48 V brushed DC motor control with PWM frequency ≤ 20 kHz.

IC Role / Device Role / Timing Role: Saturated NPN switch sinking motor current during active PWM phase.

Use Value: 40 W P_tot at T_c = 25 °C allows sustained 3 A operation with standard 10 °C/W heatsink; TO-220 tab simplifies thermal attachment.

Linear Voltage Regulator Pass Element

Relay and Solenoid Driver

Use Scenario: Series pass transistor in adjustable 0–30 V, 2 A linear bench power supply.

IC Role / Device Role / Timing Role: Continuously biased NPN operating in active region to regulate output voltage.

Use Value: 3.13 °C/W R_thj-case enables stable thermal regulation under 25 W worst-case dropout power; h_FE ≥ 10 simplifies error amplifier feedback loop design.

Use Scenario: Driving 24 V, 2.5 A industrial relay coil with 100 ms turn-on/turn-off cycles.

IC Role / Device Role / Timing Role: Switching NPN transistor providing coil current path to ground.

Use Value: 5 A I_CM accommodates relay inrush current; 100 V V_CEO withstands >60 V flyback spikes without snubber.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TIP31C	V_CEO = 100 V, I_C = 3 A, but h_FE min = 10 only at I_C = 1 A (not 3 A); R_thj-case = 3.5 °C/W	Lower h_FE at full load increases base drive requirement; slightly higher thermal resistance reduces power margin.	Acceptable where base drive capability exceeds 0.9 A and heatsink R_th ≤ 8 °C/W is available.
MJE13009	V_CEO = 400 V, I_C = 12 A, but V_CE(sat) = 2.5 V @ 8 A; TO-220FP package with insulated tab	Higher voltage rating overshoots need; higher saturation loss increases conduction heating at 3 A.	Only suitable if future-proofing for >100 V systems is required and thermal budget allows 2× conduction loss.

Compared with TIP31C and MJE13009, BD241C delivers superior h_FE stability at full 3 A load and lower thermal resistance - making it optimal for compact, thermally constrained linear and switching designs where precise base drive and heatsink efficiency matter.

Availability

BD241C is available at Aetrix Electronics and suitable for audio amplifier output stages, DC motor drivers, linear voltage regulator pass elements, and relay/solenoid drivers requiring stable component supply and consistent parametric performance across production batches.

Supply support for BD241C 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs and discrete devices for automotive, industrial, and consumer markets.

The BD241C belongs to ST's legacy power bipolar transistor family, engineered specifically for robust, cost-effective medium-power linear and switching applications where reliability under sustained thermal stress is essential.

FAQ

Is BD241C pin-compatible with BD241A or BD241B?

Yes - BD241A, BD241B, and BD241C share identical TO-220 pinout (E-C-B), package dimensions, and terminal assignments. Only absolute maximum ratings differ: V_CEO is 60 V, 80 V, and 100 V respectively. Substitution requires verifying that the higher-voltage BD241C meets or exceeds circuit voltage stress requirements.

What is the maximum allowable case temperature for continuous 3 A operation?

At I_C = 3 A and V_CE ≈ 1.2 V, power dissipation is ~3.6 W. With R_thj-case = 3.13 °C/W, junction temperature rise is ~11.3 °C. Using T_j(max) = 150 °C (from T_stg range), max case temperature is 138.7 °C - but practical design limits T_c to ≤ 100 °C to ensure long-term reliability and margin.

Does BD241C require a heatsink in 3 A switching applications?

Yes - even with 3.6 W conduction loss, ambient operation above 40 °C or pulsed duty cycles >10% necessitates a heatsink. Without one, case temperature rises rapidly due to R_thj-amb = 62.5 °C/W. A 10 °C/W heatsink keeps T_c < 75 °C at 3.6 W, preserving h_FE and preventing thermal runaway.

Can BD241C be used in complementary pair configurations with BD242C?

Yes - BD241C (NPN) and BD242C (PNP) are explicitly designed as complementary pairs with matched V_CEO (100 V), I_C (3 A), and thermal characteristics. Their h_FE curves and saturation voltages are balanced to minimize crossover distortion in Class AB amplifier outputs.

BD241C Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 3 A

Voltage - Collector Emitter Breakdown (Max):: 100 V

Vce Saturation (Max) @ Ib, Ic:: 1.2V @ 600mA, 3A

Current - Collector Cutoff (Max):: 300µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 10 @ 3A, 4V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

BD241C FAQ

1.How can I place an order for BD241C through Aetrix?

Please submit a Request for Quotation (RFQ) for BD241C 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 BD241C reliable?

The price and inventory of BD241C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD241C is usually 5 days.

3.What payment methods are accepted for BD241C?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD241C transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD241C?

BD241C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD241C 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 BD241C?

For technical support, including BD241C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD241C requirements.

6.How does Aetrix verify that BD241C is sourced from the original manufacturer or authorized distributors?

All BD241C 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 BD241C meets industry standards.

7.What is the process for return or replacement of BD241C?

All BD241C units undergo pre-shipment inspection (PSI). If there is an issue with BD241C, 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 BD241C part is unused and in its original packaging.

Return procedure for BD241C:

1.Submit a request within 90 days.

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

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