onsemi BCX17

Overview

BCX17 from ON Semiconductor is a PNP bipolar junction transistor (BJT) designed for general-purpose amplification and switching at up to 500 mA collector current. It features -45 V V_CEO, -50 V V_CBO, -5 V V_EBO, 300 mW power dissipation, and DC current gain (h_FE) ranging from 40 to 600 depending on operating conditions. It is commonly used in low-voltage power supply control and signal inversion circuits.

For engineers reviewing the BCX17 datasheet, pinout, applications, or equivalent options, this page provides verified package mapping (SOT-23), validated terminal roles (Base–Emitter–Collector), confirmed thermal resistance (417 °C/W), and two field-validated alternative parts with documented parameter trade-offs.

Technical Context

The BCX17 operates as a discrete PNP BJT with fixed emitter-base and collector-base junction structures optimized for linear amplification and saturated switching. Its h_FE variation across IC = −100 mA to −500 mA reflects intentional process tuning for stable gain in mid-current applications.

Thermal performance is defined for mounting on an alumina substrate (0.4" × 0.3" × 0.024", 9.5% Al₂O₃), yielding R_θJA = 417 °C/W - a value dependent on PCB layout and heatsinking, not intrinsic to the die alone.

Key Specifications

Pinout & Package

BCX17 is housed in a SOT-23 (JEDEC TO-236AB) 3-lead plastic surface-mount package with standardized footprint and thermal pad exposure. The package is compatible with reflow soldering per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Compared with BCX17, BC807-40 delivers tighter h_FE control for precision biasing but sacrifices saturation voltage margin, while MMBT4403 extends current capability at the cost of gain predictability and efficiency - making BCX17 the balanced choice for mixed-signal interface and medium-power switching where both gain and loss matter.

Availability

BCX17 is available at Aetrix Electronics and suitable for relay driver circuits, DC-DC converter feedback amplifiers, LED current sink switches, and linear voltage regulator pass elements requiring stable component supply across industrial and automotive production programs.

Supply support for BCX17 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global supplier of energy-efficient semiconductor components focused on power management, analog, sensors, and connectivity solutions.

The BCX17 belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, engineered for cost-sensitive, high-volume applications requiring robust DC performance and manufacturability in SOT-23 packaging.

FAQ

What is the maximum continuous collector current rating for BCX17?

The BCX17 has a maximum continuous collector current (I_C) rating of −500 mA at T_C = 25°C. This rating assumes proper thermal management on an alumina substrate; actual usable current decreases with rising case temperature due to the 2.4 mW/°C derating factor. For sustained operation near this limit, PCB copper area and airflow must be validated to keep junction temperature below 150°C. The BCX17 datasheet specifies this value under absolute maximum ratings and confirms it in electrical characteristics tables.

Does BCX17 have a documented pinout for SOT-23 package?

Yes, BCX17 uses the standard SOT-23 pinout: Pin 1 is Base, Pin 2 is Emitter, and Pin 3 is Collector - confirmed in the official BCX17 Rev. 1.1.0 datasheet Figure 1 and "Physical Dimensions" section. The marking "T1" on the top surface aligns with this orientation. This pinout is consistent across ON Semiconductor's BCX-series PNP transistors and matches JEDEC TO-236AB mechanical specifications. No alternate pinouts are documented for BCX17.

What is the typical V_CE(sat) of BCX17 under full-load switching conditions?

The BCX17 exhibits a typical V_CE(sat) of −0.62 V when operated at I_C = −500 mA and I_B = −50 mA, as specified in the Electrical Characteristics table of the BCX17 datasheet. This value represents the voltage drop across the collector-emitter junction in hard saturation and is measured at T_C = 25°C. Designers should verify this performance under actual board-level thermal conditions, as V_CE(sat) increases with junction temperature. The BCX17's low saturation voltage directly contributes to reduced power loss in switching applications.

Can BCX17 be used in linear amplifier configurations?

Yes, BCX17 is explicitly characterized for linear amplifier use, with h_FE guaranteed from 100 to 600 at I_C = −100 mA and V_CE = −1.0 V. Its gain remains usable down to I_C = −10 mA and up to −500 mA, supporting Class-A and Class-AB small-signal stages. The BCX17 datasheet includes h_FE curves versus I_C and temperature, confirming its suitability for bias-stable amplification when operated within V_CEO and P_D limits.

Is BCX17 RoHS compliant and halogen-free?

Yes, BCX17 is RoHS compliant and halogen-free, as confirmed by ON Semiconductor's official product change notices and material declarations. The device meets EU Directive 2011/65/EU and IEC 61249-2-21:2013 standards. Halogen content is below 900 ppm chlorine and 900 ppm bromine, with no intentionally added antimony trioxide or phosphorus flame retardants. This compliance applies to all BCX17 units manufactured after the Fairchild integration into ON Semiconductor, including current SOT-23 tape-and-reel shipments.