Transistors
Products (4)
BU931T - 15A, 400V NPN Power Darlington Transistor | STMicroelectronics
The BU931T is an NPN power Darlington transistor manufactured by STMicroelectronics, designed for high-current switching applications. It features a collector-emitter voltage (VCEO) of 400V, a continuous collector current (IC) of 15A, and a peak collector current of 30A. The device is housed in a TO-220 package, providing excellent thermal performance for power dissipation up to 125W. With a DC current gain (hFE) of 500 minimum at 10A, it offers high current amplification, making it suitable for motor control, power supplies, and automotive ignition systems. A Darlington transistor is a compound structure consisting of two bipolar junction transistors (BJTs) connected in a Darlington pair configuration, where the emitter of the first transistor drives the base of the second. This configuration provides extremely high current gain, typically in the range of 1000 to 10000, compared to a single BJT. Darlington transistors are widely used in high-current switching applications where a low base current is required to control a large collector current. They are part of the broader family of power transistors, which also includes MOSFETs and IGBTs, and are essential components in power electronics for amplification and switching. Key features of the BU931T include a collector-emitter saturation voltage (VCE(sat)) of 2.0V maximum at IC=10A, ensuring low power loss during conduction. The device also offers a fast switching speed with a fall time of 1.5 microseconds, making it suitable for high-frequency applications up to 10 kHz. The integrated base-emitter resistor and base-emitter diode enhance reliability by preventing spurious turn-on due to leakage currents. The TO-220 package is lead-free and RoHS compliant, meeting modern environmental standards. Technically, the BU931T utilizes a triple-diffused planar process, providing robust avalanche energy handling and a wide safe operating area (SOA). The device can withstand a collector-emitter breakdown voltage (BVCEO) of 400V and a collector-base voltage (VCBO) of 500V, ensuring high voltage robustness. The thermal resistance from junction to case (RthJC) is 1.0°C/W, allowing efficient heat transfer to an external heatsink. The operating junction temperature range is -65°C to +150°C, making it suitable for harsh environments. Typical applications include motor control circuits, switching power supplies, automotive ignition systems, and solenoid drivers. In motor control, the BU931T can switch DC motors up to 15A, providing reliable on/off control. In automotive ignition, its high voltage and current ratings ensure dependable performance in demanding conditions. The device is also used in welding equipment and battery chargers where high current switching is required. When designing with the BU931T, ensure adequate base drive current to achieve low saturation voltage. A base current of at least 1/250 of the collector current is recommended. Additionally, use a suitable heatsink to maintain junction temperature below 150°C, especially at high current levels. Proper snubber circuits may be required to protect against inductive load transients.
BU941ZT - 15A, 350V NPN Power Transistor | STMicroelectronics
The STMicroelectronics BU941ZT is a high-voltage, high-current NPN power transistor designed for demanding switching and linear applications. It delivers a continuous collector current of 15A and supports a collector-emitter voltage of 350V, making it suitable for power management, motor control, and industrial systems. The device is housed in a TO-220 package, which provides excellent thermal performance and is widely used in through-hole PCB designs. A power transistor is a three-terminal semiconductor device used to amplify or switch electronic signals and electrical power. In the hierarchy of power electronics, the BU941ZT is a bipolar junction transistor (BJT), which falls under the category of discrete semiconductors, specifically power transistors. BJTs are current-controlled devices where a small base current controls a larger collector current, enabling efficient power regulation and switching in circuits such as power supplies, inverters, and motor drivers. Key features of the BU941ZT include a high collector-emitter voltage rating of 350V, a continuous collector current of 15A, and a low saturation voltage that minimizes power loss during conduction. The device also offers a high DC current gain (hFE) for efficient base drive, and a fast switching speed suitable for applications up to several kilohertz. The TO-220 package includes a metal tab for heatsinking, allowing the transistor to dissipate significant power when properly mounted. Technically, the BU941ZT is fabricated using STMicroelectronics' advanced bipolar process, which ensures high ruggedness and reliability under stressful operating conditions. The device features a wide safe operating area (SOA) and built-in protection against overcurrent and overtemperature, making it robust for industrial environments. Its low saturation voltage (VCE(sat)) of typically 1.5V at 15A reduces conduction losses, improving overall system efficiency. Typical applications include switch-mode power supplies (SMPS), motor control circuits, inverters, and battery chargers. In an SMPS, the BU941ZT can be used as the main switching element, handling high voltages and currents while maintaining low losses. In motor control, it drives inductive loads with fast switching and high current capability. The device is also suitable for linear regulators and audio amplifiers where high power handling is required. When designing with the BU941ZT, ensure adequate base drive current to fully saturate the transistor and minimize power dissipation. Use a proper heatsink or thermal pad to manage the heat generated during operation, especially at high currents. Additionally, consider adding a flyback diode across inductive loads to protect the transistor from voltage spikes during switching.
ULN2003AD - 7-Channel Darlington Driver | Texas Instruments
The Texas Instruments ULN2003AD is a 7-channel high-voltage, high-current Darlington transistor array designed for driving inductive loads such as relays, solenoids, stepper motors, and lamps. It features seven open-collector Darlington pairs with common-cathode clamp diodes for inductive transient suppression, and is available in a 16-pin SOIC (D) package. Each channel can sink up to 500 mA continuously and 600 mA peak, with a collector-emitter voltage rating of 50 V. The device operates over a temperature range of -40°C to +105°C and is RoHS compliant. A Darlington transistor array is a semiconductor device that integrates multiple Darlington pairs, each consisting of two bipolar transistors in a configuration that provides high current gain. This category falls under the hierarchy: Darlington array -> transistor array -> discrete semiconductor -> semiconductor. The ULN2003A is a specific variant of the ULN2003 family, which is widely used in industrial and consumer applications for interfacing low-level logic signals to high-current loads. Key features include seven Darlington pairs with a total current capability of 500 mA per channel, a collector-emitter voltage rating of 50 V, and integrated clamp diodes for inductive load protection. The input is compatible with TTL and 5V CMOS logic, and the device includes a common emitter for all channels. The SOIC-16 package provides a compact footprint for space-constrained designs. The ULN2003AD uses a bipolar process technology with a high-current NPN Darlington configuration. Each channel has a base resistor (2.7 kΩ) and an emitter resistor (3.6 kΩ) to ensure proper biasing and thermal stability. The integrated clamp diodes are connected to a common cathode pin (pin 9) for easy connection to the supply rail. The device exhibits a low saturation voltage (typically 1.6 V at 350 mA) to minimize power dissipation. Typical applications include relay drivers, stepper motor drivers, solenoid drivers, and lamp drivers in industrial control, automotive, and consumer electronics. The high current gain allows direct interfacing with microcontrollers without additional driver stages, simplifying circuit design. When designing with this device, ensure that the total power dissipation does not exceed the package thermal limits. For high-current applications, consider using multiple channels in parallel or adding external heatsinking. The clamp diodes must be connected to the positive supply rail to protect against inductive kickback. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the TI datasheet, providing a comprehensive resource for engineers selecting the ULN2003AD.
VIPERGAN65 - 650V GaN Power Transistor | STMicroelectronics
The STMicroelectronics VIPERGAN65 is a 650V enhancement-mode Gallium Nitride (GaN) power transistor designed for high-efficiency power conversion applications. It integrates a GaN power HEMT with a gate driver and protection features in a compact PQFN 8x8 mm package, enabling high-frequency operation and reduced system size. What is a GaN power transistor? A Gallium Nitride (GaN) power transistor is a wide-bandgap semiconductor device that switches faster and more efficiently than traditional silicon MOSFETs. It belongs to the power transistor family, which includes MOSFETs, IGBTs, and bipolar transistors. GaN devices offer lower on-resistance and lower gate charge, making them ideal for high-frequency power converters such as AC-DC adapters, server power supplies, and wireless charging systems. Key features of the VIPERGAN65 include a 650V drain-source voltage rating, low on-resistance (RDS(on)) of [DATA_NEEDED: RDS(on)], and a gate driver with integrated protection. The device supports high switching frequencies up to [DATA_NEEDED: max switching frequency] MHz, reducing the size of magnetic components. It also features overcurrent, overtemperature, and undervoltage lockout protection, enhancing system reliability. Technically, the VIPERGAN65 uses a cascode configuration with a GaN HEMT and a silicon MOSFET, simplifying gate drive requirements. The integrated driver eliminates external gate driver components, reducing board space and design complexity. The device's fast switching transitions minimize switching losses, improving overall efficiency in power conversion. Typical applications include AC-DC adapters for laptops and smartphones, server power supplies, and LED lighting drivers. The high efficiency and small form factor make it suitable for space-constrained designs. In a 65W USB-PD adapter, the VIPERGAN65 can achieve over 93% efficiency, reducing heat dissipation and enabling compact enclosures. When designing with the VIPERGAN65, ensure proper PCB layout with short, low-inductance paths for the gate drive and power loops. Use a dedicated ground plane and place decoupling capacitors close to the device. Thermal management is critical; use a thermal pad and adequate copper area to dissipate heat from the package.