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Diodes Incorporated BCX54TA
- Part No.:
- BCX54TA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-243AA
- Datasheet:
-
BCX54TA.pdf
- Description:
- TRANS NPN 45V 1A SOT-89-3
- Quantity:
- Payment:
- Shipping:
Inventory:754
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Product details
Overview
BCX54TA from Diodes Incorporated is an NPN medium-power transistor in SOT89 package, rated for 45V VCEO, 1A continuous collector current, and <500mV VCE(sat) at 0.5A. It features epitaxial planar die construction, low thermal resistance (RθJC = 39°C/W), and is qualified for automotive-grade change control per AEC-Q101 requirements. It serves as a switching or amplification device in AF output stages and medium-power load drivers.
For engineers reviewing the BCX54TA datasheet, BCX54TA pinout, BCX54TA application, or BCX54TA equivalent, key selection criteria include its 45V breakdown rating, 1A DC current capability, SOT89 thermal performance with exposed collector pad, and complementary PNP pairing with BCX51TA - all critical for reliable medium-power discrete design.
Technical Context
The BCX54TA operates as a general-purpose NPN bipolar junction transistor optimized for linear amplification and hard-switching applications up to 100kHz. Its hFE ranges from 25–250 across 5mA–500mA IC, supporting stable biasing in Class-A and Class-AB amplifier stages.
Thermal design leverages the SOT89's exposed collector pad: RθJL is 13°C/W to solder point, and RθJC is 39°C/W to case surface - enabling 1.5W dissipation on 25mm×25mm copper when mounted per JEDEC layout guidelines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 45 V - Maximum safe collector-emitter voltage before avalanche; defines upper rail limit in switching supplies and audio output stages. |
| IC (continuous) | 1 A - Sustained DC current handling; supports driver-stage loads like relay coils or small motors without derating at 25°C ambient. |
| VCE(sat) | <500 mV @ 0.5A/50mA - Low saturation voltage minimizes conduction loss and self-heating in high-duty-cycle switching. |
| hFE | 25–250 - Wide DC current gain range enables flexible bias network design across operating currents from 5mA to 500mA. |
| fT | 150 MHz - Transition frequency supports RF pre-driver and broadband amplifier use up to ~100MHz with adequate gain margin. |
| RθJC | 39 °C/W - Junction-to-case thermal resistance confirms efficient heat transfer from die to PCB via exposed collector tab. |
Pinout & Package
Package: SOT89 - surface-mount plastic package with exposed collector pad for enhanced thermal dissipation; dimensions per Diodes DS35369 Rev. 12-2 (4.50 × 2.50 × 1.50 mm); UL 94V-0 rated molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Emitter) | E | Current sink node; connected to ground or low-side return path; requires low-impedance trace for stable biasing. |
| Pin 2 (Base) | B | Control input; driven by resistor-limited voltage source or logic-level signal; base current ≤100mA continuous. |
| Pin 3 (Collector) | C | Power output node; electrically and thermally tied to exposed metal tab; must be soldered to ≥15mm² copper for rated power handling. |
Key Features
| Feature | Design Value |
|---|---|
| Low VCE(sat) | <500 mV at 0.5A ensures ≤250 mW conduction loss, reducing thermal stress in compact layouts. |
| Exposed collector pad | Enables direct thermal coupling to PCB copper; achieves RθJA = 83°C/W on 25mm² 1oz copper - critical for unheatsinked designs. |
| AEC-Q101 readiness | Manufactured in IATF 16949-certified facilities with PPAP capability; supports automotive subsystem qualification with controlled change management. |
| Green RoHS compliance | Halogen- and antimony-free (<900 ppm Br/Cl, <1000 ppm Sb); meets EU RoHS 3 and automotive environmental standards. |
Applications
| Audio Power Amplifier Output Stage | DC Motor Driver Switch |
|---|---|
Use Scenario: Final push-pull stage in 1–3W portable audio amplifiers driving 4–8Ω speakers. IC Role / Device Role / Timing Role: NPN complement in Class-AB output pair; handles positive half-cycle current delivery with low distortion. Use Value: 45V VCEO and 1A IC support ±12V rails and transient speaker loads; VCE(sat) <500mV reduces crossover distortion and heatsink requirements. |
Use Scenario: Unidirectional drive for brushed DC motors in automotive HVAC actuators or industrial positioners. IC Role / Device Role / Timing Role: High-side or low-side switch controlling motor current up to 800mA continuous. Use Value: 2A ICM peak rating accommodates motor startup surges; exposed collector pad maintains TJ <125°C under 100% duty cycle at 750mA. |
| Relay Coil Driver | LED Current Regulator |
Use Scenario: Driving 12V/24V electromagnetic relays in PLC I/O modules and building automation panels. IC Role / Device Role / Timing Role: Saturated switch providing full coil current (typically 30–100mA) with minimal voltage drop. Use Value: VCE(sat) <500mV ensures >95% coil voltage delivery; hFE ≥100 at 50mA simplifies base drive resistor selection. |
Use Scenario: Constant-current sink for high-brightness LED strings in automotive interior lighting or signage. IC Role / Device Role / Timing Role: Linear current regulator using emitter-degeneration resistor; sets precise LED current independent of supply variance. Use Value: Tight hFE tolerance (25–250) and low VBE(on) (≤1.0V) enable stable 100–500mA regulation with <±3% drift over temperature. |
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 |
|---|---|---|---|
| BCX55TA | VCEO = 60V, VCBO = 60V - 15V higher breakdown than BCX54TA; otherwise identical pinout, package, and gain profile. | Required where system transients exceed 45V or where 20% voltage margin is mandated (e.g., 48V industrial bus interfaces). | Select BCX55TA when operating from ≥40V rails or when long-term reliability demands higher voltage headroom. |
| MJD127G | TO-252 package, 80V VCEO, 2A IC, RθJC = 3°C/W - significantly higher power handling but larger footprint and different thermal interface. | Suitable for >1.5W continuous dissipation or forced-air-cooled systems where SOT89 thermal limits are exceeded. | Choose MJD127G only when BCX54TA's 1.5W max on 25mm² copper is insufficient - not a drop-in replacement due to package and pinout mismatch. |
Compared with BCX55TA, BCX54TA trades 15V breakdown margin for tighter voltage tolerance in 36–45V systems; versus MJD127G, it offers 60% smaller board area and simpler reflow assembly at the cost of 30% lower power capacity.
Availability
BCX54TA is available at Aetrix Electronics and suitable for audio amplifier output stages, DC motor drivers, relay coil interfaces, and LED current regulation requiring stable component supply, automotive-grade traceability, and RoHS-compliant manufacturing.
Supply support for BCX54TA 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, specializing in high-reliability components for automotive, industrial, and consumer markets with IATF 16949-certified production.
The BCX54 series belongs to Diodes' general-purpose bipolar transistor product line, engineered for robust medium-power switching and linear amplification in space-constrained, thermally demanding environments.
FAQ
What is the maximum continuous power dissipation for BCX54TA on a standard PCB?
BCX54TA delivers 1.5W maximum continuous power dissipation when mounted on 25mm × 25mm of 1oz copper per Diodes' recommended layout (Note 7, DS35369). This assumes still-air conditions and accounts for RθJA = 83°C/W. Derating begins above +25°C ambient at 12mW/°C.
Is BCX54TA pin-compatible with BCX55TA and BCX56TA?
Yes - BCX54TA, BCX55TA, and BCX56TA share identical SOT89 package, pinout (E-B-C), marking layout, and mechanical dimensions. Only electrical ratings differ: VCEO is 45V, 60V, and 80V respectively. No PCB redesign is needed when upgrading voltage grade.
Does BCX54TA require a heatsink in typical applications?
No external heatsink is required if PCB copper area meets Diodes' guidelines: ≥15mm² for 1W, ≥25mm² for 1.5W. The exposed collector pad conducts heat directly into the board; thermal vias to inner layers further improve performance. Heatsinks are unnecessary unless ambient exceeds +70°C or power exceeds 1.2W.
Can BCX54TA be used in automotive applications?
Yes - BCX54TA is manufactured in IATF 16949-certified facilities and supports PPAP documentation. While not pre-qualified to AEC-Q101 out-of-box, Diodes provides AEC-Q101 qualification support upon request for automotive programs, including change control and lot traceability.
BCX54TA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-243AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 1 A
- Voltage - Collector Emitter Breakdown (Max):
- 45 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 50mA, 500mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 40 @ 150mA, 2V
- Power - Max:
- 1 W
- Frequency - Transition:
- 150MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
BCX54TA FAQ
1.How can I place an order for BCX54TA through Aetrix?
Please submit a Request for Quotation (RFQ) for BCX54TA 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 BCX54TA reliable?
The price and inventory of BCX54TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCX54TA is usually 5 days.
3.What payment methods are accepted for BCX54TA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCX54TA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BCX54TA?
BCX54TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BCX54TA 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 BCX54TA?
For technical support, including BCX54TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCX54TA requirements.
6.How does Aetrix verify that BCX54TA is sourced from the original manufacturer or authorized distributors?
All BCX54TA 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 BCX54TA meets industry standards.
7.What is the process for return or replacement of BCX54TA?
All BCX54TA units undergo pre-shipment inspection (PSI). If there is an issue with BCX54TA, 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 BCX54TA part is unused and in its original packaging.
Return procedure for BCX54TA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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