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

Nexperia USA Inc. BCX54-QX

Name: BCX54-QX
Brand: Nexperia USA Inc.
SKU: BCX54-QX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BCX54-QX

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: BCX54-QX.pdf

Description:: TRANS NPN 45V 1A SOT-89

Quantity:: RFQ Add To RFQ list

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Inventory:4,529

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Product details

Overview

BCX54-Q from Nexperia is an AEC-Q101-qualified NPN medium power transistor in SOT89 (SC-62) package, rated for 45 V V_CEO, 1 A continuous collector current, and 1.35 W power dissipation on 6 cm² copper pad - used as low-side switch or MOSFET driver in automotive linear regulators and battery-powered power management circuits.

For engineers reviewing the BCX54-Q datasheet, BCX54-Q pinout, BCX54-Q application, or BCX54-Q equivalent, this page delivers verified electrical specs, thermal derating behavior, junction-to-ambient resistance under three PCB mounting conditions, and validated automotive-grade reliability data per IEC 60134 absolute maximum ratings.

Technical Context

This discrete NPN bipolar junction transistor operates in linear or saturated switching mode with DC current gain (h_FE) ranging 63–250 at V_CE = 2 V and I_C = 150 mA, and transition frequency f_T of 100–180 MHz at V_CE = 5 V, I_C = 50 mA. It supports pulsed peak collector current up to 2 A (t_p ≤ 1 ms).

Thermal performance is defined across three PCB configurations: R_th(j-a) = 250 K/W (standard footprint), 132 K/W (1 cm² collector pad), and 93 K/W (6 cm² collector pad). Junction temperature is rated to 150 °C, with storage range from –65 °C to 150 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage with base open; defines upper rail limit in low-side switch or regulator pass transistor applications.
I_C	1 A continuous - Sustained collector current capability at T_amb ≤ 25 °C; determines load-driving capacity in power management stages.
h_FE	63–250 - DC current gain at V_CE = 2 V, I_C = 150 mA; enables predictable base drive sizing for saturation control.
V_CE(sat)	≤ 0.5 V at I_C = 500 mA, I_B = 50 mA - Low saturation voltage minimizes conduction loss in switching applications.
P_tot	1.35 W - Total power dissipation with 6 cm² copper pad; sets thermal design margin for sustained operation in enclosed automotive modules.
f_T	100–180 MHz - Transition frequency confirms suitability for high-speed switching or RF amplifier biasing up to ~100 MHz.
R_th(j-a)	93 K/W - Thermal resistance with 6 cm² collector pad; enables calculation of junction temperature rise under real PCB layout conditions.

Pinout & Package

SOT89 (SC-62) surface-mount plastic package with exposed die pad for enhanced thermal transfer; 3-pin flat-lead configuration optimized for power dissipation on FR4 PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current return path; connected to ground or low-side reference in switch/driver configurations.
2	Collector	Main power output terminal; soldered to large copper area for heat sinking in power regulation or motor drive stages.
3	Base	Control input; requires current-limited drive (≤ 0.3 A peak) to ensure reliable saturation without overdrive stress.

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive use per Stress Test Qualification for Discrete Semiconductors - supports deployment in engine control, body electronics, and ADAS subsystems.
Three h_FE variants	BCX54-Q (63–250), BCX54-10-Q (63–160), BCX54-16-Q (100–250) - enables precise gain matching for production consistency in feedback loops or current-sense amplifiers.
Exposed collector pad	Integral thermal path to PCB copper - reduces R_th(j-a) by up to 63% vs. standard footprint, critical for thermally constrained automotive modules.
High I_CM	2 A peak (t_p ≤ 1 ms) - supports surge-current handling in motor startup, solenoid actuation, or inrush-limited battery charging circuits.

Applications

Linear Voltage Regulators

MOSFET Drivers

Use Scenario: Pass transistor in adjustable LDO or series regulator for 12 V automotive systems.

IC Role / Device Role / Timing Role: NPN medium-power pass element controlling output voltage via base bias feedback loop.

Use Value: 45 V rating accommodates load-dump transients; 1.35 W P_tot enables stable regulation under 500 mA load at ambient up to 85 °C.

Use Scenario: Gate driver stage for N-channel power MOSFETs in BLDC motor controllers.

IC Role / Device Role / Timing Role: Current-amplifying switch translating microcontroller GPIO logic into sufficient gate charge current.

Use Value: 2 A I_CM supports fast MOSFET turn-on; V_CE(sat) ≤ 0.5 V minimizes driver-stage conduction loss during PWM cycles.

Low-Side Switches

Battery-Driven Devices

Use Scenario: Load switch for headlights, HVAC actuators, or fuel pump control in 12/24 V vehicle networks.

IC Role / Device Role / Timing Role: Ground-referenced switching element enabling ON/OFF control of resistive or inductive loads.

Use Value: AEC-Q101 qualification ensures reliability across –40 °C to 125 °C operating range; 45 V V_CEO withstands ISO 7637-2 pulse 5a.

Use Scenario: Power path control in portable diagnostic tools or telematics modules powered by 12 V lead-acid or LiFePO₄ packs.

IC Role / Device Role / Timing Role: Reverse-polarity and overcurrent protected main power switch upstream of DC-DC converters.

Use Value: 1 A I_C supports typical 500–800 mA system loads; thermal derating curves allow accurate lifetime estimation on compact PCBs.

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
BCX56-Q	Higher V_CEO = 60 V; same SOT89 package and AEC-Q101 qualification.	Better suited for 24 V commercial vehicle systems with higher transient margins.	Select when V_CEO > 45 V is required; otherwise identical thermal and gain behavior.
MMBT5551	Lower I_C = 600 mA; TO-236 (SOT-23) package; no AEC-Q101 qualification.	Limited to non-automotive consumer or industrial signal-switching roles.	Use only in cost-sensitive, non-automotive designs where 1 A current and automotive qualification are not needed.

Compared with BCX54-Q, BCX56-Q extends voltage headroom without sacrificing thermal or gain characteristics, while MMBT5551 trades current capability, ruggedness, and qualification for smaller size and lower cost in non-automotive contexts.

Availability

BCX54-Q is available at Aetrix Electronics and suitable for automotive power management, battery-driven device control, and low-side switching applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BCX54-Q 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

Nexperia is a global semiconductor expert focused on essential efficiency technologies, delivering high-performance, high-reliability discrete, logic, and MOSFET solutions for automotive, industrial, and mobile markets.

The BCX54-Q belongs to Nexperia's AEC-Q101-qualified bipolar transistor product line, engineered specifically for robust, thermally efficient switching and amplification in automotive power control and battery management systems.

FAQ

What is the maximum allowable junction temperature for BCX54-Q?

The absolute maximum junction temperature (T_j) is 150 °C per IEC 60134 limiting values. Operation above this threshold risks permanent degradation. Derating must follow published R_th(j-a) curves based on actual PCB copper area - e.g., with 6 cm² collector pad, ambient must stay below 105 °C at full 1 A load to maintain T_j ≤ 150 °C.

Is BCX54-Q pin-compatible with BCX55-Q or BCX56-Q?

Yes - all three share identical SOT89 (SC-62) pinning: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. They differ only in V_CEO (45 V, 50 V, 60 V respectively) and minor h_FE distribution, allowing direct substitution where voltage rating permits.

How does thermal performance change with PCB copper area?

R_th(j-a) improves from 250 K/W (standard footprint) to 132 K/W (1 cm² pad) and 93 K/W (6 cm² pad). At 1 A and 25 °C ambient, junction temperature rises by 250 °C, 132 °C, or 93 °C respectively - meaning only the 6 cm² configuration sustains safe operation without forced cooling.

Can BCX54-Q be used in linear amplifier configurations?

Yes - its f_T of 100–180 MHz and h_FE stability across I_C = 5 mA to 500 mA support Class-A or AB audio and signal amplification up to ~10 MHz. However, linear operation demands careful thermal design due to P_tot limits; V_CE should be kept ≥ 2 V to avoid second breakdown.

BCX54-QX Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

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:: 63 @ 150mA, 2V

Power - Max:: 500 mW

Frequency - Transition:: 180MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89

BCX54-QX FAQ

1.How can I place an order for BCX54-QX through Aetrix?

Please submit a Request for Quotation (RFQ) for BCX54-QX 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 BCX54-QX reliable?

The price and inventory of BCX54-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCX54-QX is usually 5 days.

3.What payment methods are accepted for BCX54-QX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCX54-QX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCX54-QX?

BCX54-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCX54-QX 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 BCX54-QX?

For technical support, including BCX54-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCX54-QX requirements.

6.How does Aetrix verify that BCX54-QX is sourced from the original manufacturer or authorized distributors?

All BCX54-QX 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 BCX54-QX meets industry standards.

7.What is the process for return or replacement of BCX54-QX?

All BCX54-QX units undergo pre-shipment inspection (PSI). If there is an issue with BCX54-QX, 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 BCX54-QX part is unused and in its original packaging.

Return procedure for BCX54-QX:

1.Submit a request within 90 days.

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

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