Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Nexperia USA Inc. BCX55-QX

Name: BCX55-QX
Brand: Nexperia USA Inc.
SKU: BCX55-QX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BCX55-QX

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: BCX55-QX.pdf

Description:: TRANS NPN 60V 1A SOT-89

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:9,082

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BCX55-Q from Nexperia is an AEC-Q101-qualified NPN medium power transistor in SOT89 (SC-62) package, rated for 60 V V_CEO, 1 A continuous collector current, and 1.35 W total power dissipation with 6 cm² copper pad. It delivers h_FE = 63–250 at I_C = 150 mA and is optimized for automotive-grade low-side switching in linear voltage regulators and MOSFET drivers.

For engineers reviewing the BCX55-Q datasheet, BCX55-Q pinout, BCX55-Q application, or BCX55-Q equivalent, this page provides verified thermal resistance values (R_th(j-sp) = 16 K/W), pulsed current capability (I_CM = 2 A), breakdown voltages (V_(BR)CEO = 60 V), saturation performance (V_CEsat ≤ 0.5 V @ I_C/I_B = 10), and AEC-Q101 qualification status - all critical for automotive power stage design validation.

Technical Context

This transistor operates as a medium-power NPN switch with exposed die pad for direct thermal conduction to PCB copper. Its three h_FE variants (BCX55-Q, -10-Q, -16-Q) enable precise gain matching across production batches without circuit redesign.

Designed for operation up to T_j = 150 °C, it supports stable DC and pulsed switching in ambient ranges from −55 °C to +150 °C. Thermal resistance varies significantly with PCB mounting: R_th(j-a) = 250 K/W (standard footprint) down to 93 K/W (6 cm² collector pad), enabling scalable thermal management.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60 V - Maximum safe collector-emitter voltage under open-base condition; defines upper rail limit in 48 V automotive systems.
I_C	1 A continuous - Sustained DC load current capability; sufficient for driving gate capacitance of high-side N-channel MOSFETs.
h_FE	63–250 @ V_CE = 2 V, I_C = 150 mA - Gain range enables predictable base drive sizing for low-side switch applications.
V_CEsat	≤ 0.5 V @ I_C = 500 mA, I_B = 50 mA - Low saturation voltage minimizes conduction loss and self-heating in linear regulator pass elements.
R_th(j-sp)	16 K/W - Junction-to-solder-point thermal resistance confirms efficient heat transfer from die to PCB via exposed collector pad.
f_T	100–180 MHz - Transition frequency supports fast switching in PWM-driven battery management and amplifier bias circuits.
AEC-Q101	Qualified - Meets stress test requirements for discrete semiconductors in automotive applications; no additional qualification needed.

Pinout & Package

SOT89 (SC-62) surface-mount plastic package with exposed collector pad for enhanced thermal and electrical conductivity. Dimensions: 4.6 mm × 2.6 mm × 1.8 mm; standard footprint per Figure 10 in datasheet Rev. 2.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current return path; connected to ground or low-side reference in switch configurations.
2	Collector	Main power output terminal; electrically and thermally tied to exposed pad for PCB heat sinking.
3	Base	Control input; requires current-limited drive (max I_B = 0.3 A) to ensure safe saturation.

Key Features

Feature	Design Value
Exposed collector pad	Enables direct thermal coupling to PCB copper area; reduces R_th(j-a) by up to 63% vs. standard SOT89 footprint.
Three h_FE bins	BCX55-Q (63–250), BCX55-10-Q (63–160), BCX55-16-Q (100–250) - simplifies gain-critical designs without custom trimming.
AEC-Q101 qualification	Validated for automotive underhood environments including temperature cycling, HTRB, and ESD testing per JESD22-A108.
High peak current rating	I_CM = 2 A (tp ≤ 1 ms) - supports surge handling in motor driver pre-driver stages and battery protection circuits.
Low V_BE	≤ 1 V @ I_C = 500 mA - reduces base drive power loss and eases compatibility with 3.3 V/5 V logic-level controllers.

Applications

Linear Voltage Regulators

Power Management

Use Scenario: Used as pass transistor in adjustable LDOs supplying 3.3 V or 5 V rails to microcontrollers in automotive body control modules.

IC Role / Device Role / Timing Role: NPN pass element regulating output voltage via emitter-follower configuration with feedback to base.

Use Value: V_CEsat ≤ 0.5 V ensures <100 mW dropout loss at 200 mA load, minimizing thermal stress in confined enclosures.

Use Scenario: Implements current-sense amplification and overcurrent shutdown in 12 V/24 V DC-DC converter secondary-side monitoring.

IC Role / Device Role / Timing Role: Discrete NPN switch controlling gate of protection MOSFET based on comparator output.

Use Value: 60 V V_CEO rating allows direct interface with 48 V architectures without level-shifting components.

Low-Side Switches

MOSFET Drivers

Use Scenario: Controls solenoid valves and LED arrays in ADAS lighting and HVAC actuators.

IC Role / Device Role / Timing Role: Ground-referenced switching element turning on/off inductive loads with flyback diode integration.

Use Value: I_CM = 2 A handles 10× inrush current of 100 mA solenoids, preventing premature failure during cold-start conditions.

Use Scenario: Drives gate of high-side N-channel MOSFETs in half-bridge motor drivers for EPS and power seats.

IC Role / Device Role / Timing Role: NPN pre-driver stage providing fast turn-on current (I_B = 50 mA) to charge gate capacitance.

Use Value: f_T ≥ 100 MHz ensures <100 ns rise/fall times for PWM frequencies up to 20 kHz with minimal shoot-through risk.

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
BCX54-Q	PNP complement; identical V_CEO, I_C, and package but opposite polarity.	Required only in complementary push-pull or high-side switch topologies where PNP sourcing is needed.	Select when designing symmetrical output stages or needing matched thermal behavior in dual-rail regulators.
ZTX653	Higher V_CEO = 100 V; h_FE = 100–800; TO-92 package; not AEC-Q101 qualified.	Suitable for industrial 48 V systems requiring higher voltage margin but not automotive deployment.	Choose for non-automotive applications needing wider V_CEO headroom and higher gain, accepting larger footprint and no automotive qualification.

Compared with BCX54-Q and ZTX653, BCX55-Q uniquely combines AEC-Q101 compliance, SOT89 thermal efficiency, and tightly binned h_FE - making it the only option qualified for direct use in automotive low-side switching without derating or requalification.

Availability

BCX55-Q is available at Aetrix Electronics and suitable for automotive body electronics, industrial power supplies, and battery-powered motor control systems requiring stable component supply and long-term lifecycle support.

Supply support for BCX55-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 high-volume, high-reliability essential semiconductors for automotive, industrial, and consumer markets.

The BCX55-Q belongs to Nexperia's AEC-Q101-qualified medium-power transistor family, engineered specifically for robust, thermally efficient switching in automotive power management and actuator control.

FAQ

What is the maximum allowable junction temperature for BCX55-Q?

The absolute maximum junction temperature (T_j) is 150 °C per IEC 60134 limiting values. Operation above this threshold risks permanent degradation. Derating is required above Tamb = 25 °C: P_tot decreases linearly to zero at 150 °C when mounted on FR4 with 6 cm² collector pad (R_th(j-a) = 93 K/W).

Does BCX55-Q require a heatsink for 1 A continuous operation?

No external heatsink is required if mounted on FR4 PCB with ≥6 cm² copper area connected to the exposed collector pad. Under those conditions, R_th(j-a) = 93 K/W allows full 1 A operation at Tamb ≤ 75 °C. With standard footprint (R_th(j-a) = 250 K/W), continuous 1 A is only possible below Tamb ≈ 35 °C.

How does the BCX55-Q differ from BCX55-16-Q in practical design?

BCX55-16-Q guarantees minimum h_FE = 100 at I_C = 150 mA, while BCX55-Q starts at h_FE = 63. This allows tighter base resistor tolerance in BCX55-16-Q designs, reducing variation in saturation depth and improving consistency in production across temperature extremes.

Can BCX55-Q be used in linear amplifier configurations?

Yes - its f_T ≥ 100 MHz, low V_CEsat, and stable h_FE over I_C = 5 mA to 500 mA support Class-A and AB audio/precision amplifier stages. However, thermal design must account for dissipation: at 500 mA and V_CE = 2 V, P_D = 1 W requires ≥6 cm² copper pad to maintain T_j < 125 °C.

BCX55-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):: 60 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

BCX55-QX FAQ

1.How can I place an order for BCX55-QX through Aetrix?

Please submit a Request for Quotation (RFQ) for BCX55-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 BCX55-QX reliable?

The price and inventory of BCX55-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCX55-QX is usually 5 days.

3.What payment methods are accepted for BCX55-QX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCX55-QX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCX55-QX?

BCX55-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCX55-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 BCX55-QX?

For technical support, including BCX55-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCX55-QX requirements.

6.How does Aetrix verify that BCX55-QX is sourced from the original manufacturer or authorized distributors?

All BCX55-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 BCX55-QX meets industry standards.

7.What is the process for return or replacement of BCX55-QX?

All BCX55-QX units undergo pre-shipment inspection (PSI). If there is an issue with BCX55-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 BCX55-QX part is unused and in its original packaging.

Return procedure for BCX55-QX:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…