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

Diodes Incorporated BCX41TA

Name: BCX41TA
Brand: Diodes Incorporated
SKU: BCX41TA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BCX41TA

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BCX41TA.pdf

Description:: TRANS NPN 125V 0.8A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:12,106

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Product details

Overview

BCX41TA from Diodes Incorporated is a 125V NPN medium-power transistor in SOT23 package, designed for high-voltage switching and amplification in industrial power supplies, relay drivers, and LED ballasts. It delivers 800mA continuous collector current, 125V V_CEO, and 100MHz transition frequency with verified thermal resistance of 403°C/W (J-A) on standard FR-4 PCB.

For engineers reviewing the BCX41TA datasheet, BCX41TA pinout, BCX41TA application, or BCX41TA equivalent, key selection criteria include breakdown voltage margin (>125V), saturation performance at IC/IB = 10 and 50, junction-to-ambient thermal derating behavior, and SOT23 lead-free compliance for automotive-adjacent industrial designs.

Technical Context

This NPN bipolar junction transistor operates as a medium-power switch or linear amplifier with fixed-emitter configuration. Its 125V V_CBO and V_CEO ratings enable use in 100V-class DC bus interfaces, while its 310mW power dissipation (on minimum pad layout) and 403°C/W R_θJA define thermal limits under steady-state conduction.

The device exhibits h_FE ranging from 25 to 400 across 100µA–200mA I_C, with V_CE(sat) ≤ 0.9V at I_C = 300mA/I_B = 30mA and f_T = 100MHz at 10mA/5V - confirming suitability for low-frequency switching (<1MHz) and analog gain stages where bandwidth and saturation voltage are jointly constrained.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	125 V - Supports operation in 100V DC supply rails with 25% safety margin against transients
I_C (continuous)	800 mA - Enables direct drive of small relays, solenoids, or LED strings without external buffering
f_T	100 MHz - Confirms usable bandwidth for audio-frequency amplification and <1MHz PWM switching
V_CE(sat)	≤ 0.9 V @ 300mA/30mA - Limits conduction loss to <270mW at rated switching current
R_θJA	403 °C/W - Requires ≥15mm² copper pour for full 310mW power handling at +25°C ambient
ESD HBM	4000 V - Allows safe manual handling and board-level assembly without special ESD controls

Pinout & Package

SOT23 plastic surface-mount package with matte tin-plated leads, UL 94V-0 flammability rating, and moisture sensitivity level 1 (MSL-1). Weight: 0.008 g.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-side return path; must handle full load current with minimal trace resistance
2 (Base)	Control input	Driven by microcontroller GPIO or logic buffer; requires series resistor to limit I_B ≤ 100mA
3 (Collector)	High-side output node	Switches positive rail up to 125V; connects to load anode or relay coil top end

Key Features

Feature	Design Value
125V breakdown rating	Enables direct interface with 48V–100V industrial DC systems without cascaded protection
Lead-free & halogen-free	Complies with RoHS 3 (2015/863/EU) and automotive-qualifiable BCX41Q variant exists
310mW power rating	Supports thermally constrained layouts in space-limited modules like smart sensors and PLC I/O cards
4000V HBM ESD tolerance	Reduces need for external TVS diodes in non-harsh-environment control boards

Applications

Industrial Power Supply Control

LED Constant-Current Driver

Use Scenario: Switching MOSFET gate driver stage in offline AC-DC auxiliary supplies.

IC Role / Device Role / Timing Role: NPN switch level-shifting 5V logic to 12–24V gate drive rail.

Use Value: 125V V_CEO prevents breakdown during transformer leakage spikes; 0.9V V_CE(sat) minimizes driver-stage conduction loss.

Use Scenario: Linear current regulator for high-brightness LED strings in signage and lighting fixtures.

IC Role / Device Role / Timing Role: Pass transistor controlled by op-amp feedback loop.

Use Value: Stable h_FE over 100µA–200mA ensures consistent current regulation; 100MHz f_T supports fast loop response.

Relay and Solenoid Driver

Signal-Level Amplifier Stage

Use Scenario: Microcontroller-driven interface to 24V/12V electromechanical relays in building automation panels.

IC Role / Device Role / Timing Role: Low-side switch controlling relay coil return path.

Use Value: 800mA I_C handles typical 24V relay coils (30–150mA); SOT23 footprint saves board area vs. TO-92.

Use Scenario: Pre-amplifier stage in sensor signal conditioning circuits for pressure or temperature transducers.

IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with fixed bias.

Use Value: 25–400 h_FE range allows predictable gain tuning; 12pF C_obo preserves signal integrity up to 100kHz.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZTX450	V_CEO = 150V, I_C = 1A, SOT89 package (larger thermal mass)	Better thermal performance but requires larger PCB footprint and different mounting	Select when >350mW continuous dissipation or >125°C ambient operation is required
BC817-40	V_CEO = 45V, I_C = 500mA, same SOT23 package and marking style	Limited to ≤48V systems; lower voltage headroom increases risk of avalanche in transient conditions	Select only for cost-sensitive 5–24V logic-level switching where 125V margin is unnecessary

Compared with ZTX450 and BC817-40, BCX41TA uniquely balances 125V robustness, SOT23 compactness, and 800mA drive capability - making it optimal for space-constrained industrial controls operating near 100V DC rails.

Availability

BCX41TA is available at Aetrix Electronics and suitable for industrial power supply control, LED constant-current drivers, relay/solenoid drivers, and signal-level amplifier stages requiring stable component supply and RoHS-compliant sourcing.

Supply support for BCX41TA 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.

The BCX41 belongs to Diodes' general-purpose bipolar transistor product line, engineered for reliability in industrial, consumer, and automotive-qualified (via BCX41Q) power interface applications.

FAQ

What is the maximum allowable base current for BCX41TA?

The absolute maximum base current is 100mA per the datasheet's Absolute Maximum Ratings table. In practice, base current should be limited to ≤30mA for reliable 300mA collector switching, as validated in the V_CE(sat) test condition (I_C/I_B = 10). Exceeding 100mA risks metallization failure or bond wire damage.

Can BCX41TA replace BCX41 in existing designs?

Yes - BCX41TA is the tape-and-reel packaged version of BCX41, identical in electrical and thermal specifications. The "TA" suffix denotes SOT23 packaging on 8mm tape with 3,000-unit reels, matching the mechanical data, marking ("EK"), and absolute ratings of the base BCX41 part.

Does BCX41TA meet automotive qualification standards?

No - BCX41TA is not AEC-Q101 qualified. However, Diodes offers the functionally identical BCX41Q variant, which undergoes full AEC-Q101 stress testing and is documented in a separate automotive-grade datasheet (DS33007Q).

What is the recommended PCB pad layout for thermal performance?

Per Diodes' suggested layout, use 15mm × 15mm single-sided 1oz copper on FR-4 to achieve the 350mW power rating and 357°C/W R_θJA. Minimum pad dimensions are C = 2.0mm, X = 0.8mm, X1 = 1.35mm, Y = 0.9mm, Y1 = 2.9mm - all specified in mm on page 6 of DS33007 Rev. 5-2.

BCX41TA 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):: 800 mA

Voltage - Collector Emitter Breakdown (Max):: 125 V

Vce Saturation (Max) @ Ib, Ic:: 900mV @ 30mA, 300mA

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 25 @ 100µA, 1V

Power - Max:: 330 mW

Frequency - Transition:: 100MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

BCX41TA FAQ

1.How can I place an order for BCX41TA through Aetrix?

Please submit a Request for Quotation (RFQ) for BCX41TA 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 BCX41TA reliable?

The price and inventory of BCX41TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCX41TA is usually 5 days.

3.What payment methods are accepted for BCX41TA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCX41TA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCX41TA?

BCX41TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCX41TA 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 BCX41TA?

For technical support, including BCX41TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCX41TA requirements.

6.How does Aetrix verify that BCX41TA is sourced from the original manufacturer or authorized distributors?

All BCX41TA 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 BCX41TA meets industry standards.

7.What is the process for return or replacement of BCX41TA?

All BCX41TA units undergo pre-shipment inspection (PSI). If there is an issue with BCX41TA, 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 BCX41TA part is unused and in its original packaging.

Return procedure for BCX41TA:

1.Submit a request within 90 days.

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

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