onsemi BDX53C

Overview

BDX53C from onsemi is an NPN silicon Darlington power transistor in TO-220 package, designed for medium-power linear amplification and low-speed switching. It delivers 8.0 A continuous collector current, sustains 100 Vdc collector-emitter voltage (VCEO(sus)), and exhibits typical DC current gain (hFE) of 2500 at 4.0 A - enabling high-current drive with minimal base drive in motor control and power supply regulator circuits.

For engineers reviewing the BDX53C datasheet, pinout, applications, or equivalent options, key selection considerations include its built-in base-emitter shunt resistors, 65 W total device dissipation at TC = 25°C, thermal resistance RJC = 1.92°C/W, and RoHS-compliant Pb-free TO-220 construction suitable for industrial-grade power stage designs.

Technical Context

The BDX53C implements a monolithic Darlington pair with integrated base-emitter shunt resistors to ensure reliable turn-off and reduce external component count. Its architecture supports linear operation up to 150°C junction temperature and handles pulsed currents up to 12 A while maintaining safe operating area (SOA) compliance under DC and short-pulse conditions.

It operates as a high-gain, medium-voltage switch or amplifier with VCE(sat) ≤ 2.0 V at IC = 3.0 A / IB = 12 mA, VBE(sat) ≤ 2.5 V, and Cob = 300 pF at VCB = 10 V - making it suitable for applications requiring robust current gain and moderate switching speed without gate drivers.

Key Specifications

Pinout & Package

BDX53C is housed in a TO-220 plastic package (Case 221A, Style 1), with electrically isolated collector tab for direct heatsink mounting. The case outline conforms to JEDEC TO-220 standard dimensions (A = 14.48–15.75 mm, K = 12.70–14.27 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TIP142 and MJD127G, the BDX53C offers superior thermal performance (1.92°C/W), higher guaranteed power handling (65 W), and through-hole serviceability - making it the preferred choice for industrial power stages demanding reliability, repairability, and sustained high-current operation.

Availability

BDX53C is available at Aetrix Electronics and suitable for industrial motor control, linear power supply regulation, and AC/DC protection circuits requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for BDX53C 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BDX53C belongs to onsemi's Plastic Medium-Power Complementary Silicon Transistors product line, engineered for general-purpose amplifier and low-speed switching applications where high DC gain, rugged packaging, and thermal reliability are essential.

FAQ

What is the maximum continuous collector current rating for the BDX53C?

The BDX53C is rated for 8.0 Adc continuous collector current at case temperature TC = 25°C. This rating assumes proper heatsinking to maintain junction temperature within −65°C to +150°C limits. At elevated case temperatures, current must be derated per the power derating curve in Figure 1 of the datasheet - for example, at TC = 100°C, maximum IC drops to approximately 4.5 A to stay within safe SOA boundaries.

Does the BDX53C have built-in base-emitter resistors, and what is their function?

Yes, the BDX53C features monolithic construction with built-in base-emitter shunt resistors. These resistors provide a defined discharge path for stored base charge, ensuring rapid and reliable turn-off without requiring external pull-down components - a critical feature for noise-immune operation in industrial control environments where signal integrity is compromised by EMI or long cable runs.

What is the safe operating area (SOA) limitation for the BDX53C at DC operation?

The BDX53C's DC safe operating area is defined in Figure 5 of the datasheet and is bounded by thermal limits (65 W at TC = 25°C) and second breakdown. At VCE = 40 V, the maximum allowable IC is ~4.5 A; at VCE = 100 V, it drops to ~0.8 A. Exceeding these boundaries risks permanent device failure due to localized thermal runaway or secondary breakdown, especially under sustained DC bias without adequate heatsinking.

Can the BDX53C be used in complementary pairs with PNP devices, and which part is specified for that role?

Yes, the BDX53C is explicitly designed as the NPN complement to the BDX54C PNP transistor. Both share identical voltage ratings (VCEO(sus) = 100 Vdc), current capability (8.0 Adc), thermal characteristics (RJC = 1.92°C/W), and TO-220 packaging - enabling matched push-pull amplifier stages, H-bridge motor drivers, and symmetrical power supply designs without gain or thermal mismatch concerns.

Is the BDX53C RoHS-compliant and lead-free, and how is this indicated in the marking?

Yes, the BDX53C is RoHS-compliant and Pb-free, as confirmed in the datasheet's "Features" section and ordering information. This is denoted in the device marking by the suffix "G" - e.g., BDX53CG - and verified by onsemi's Pb-Free Packaging documentation. The device meets JEDEC J-STD-609 Category 1a requirements and supports standard lead-free reflow soldering profiles up to 260°C peak temperature.