Infineon BCR141W: A Comprehensive Technical Overview and Application Note
The Infineon BCR141W is a silicon-based, digital transistor (resistor-equipped transistor) designed to replace a single device and its external base resistor, simplifying circuit design and saving valuable PCB space. As part of Infineon's extensive portfolio of small-signal devices, it is engineered for high integration and reliability in switching and amplification applications, particularly where microcontroller interfaces are involved.
This device integrates a bias resistor network directly within the same package as the bipolar transistor. The BCR141W is an NPN transistor with a series base resistor (R1 = 10 kΩ) and a base-emitter resistor (R2 = 10 kΩ). This integration offers several key advantages:
Reduced Component Count: Eliminates the need for external discrete resistors.
Improved Manufacturing Efficiency: Simplifies automated PCB assembly by reducing placement operations.
Enhanced Circuit Reliability: Minimizes soldering points and potential failure modes.
Optimized Board Layout: Saves space, enabling more compact and cost-effective designs.
Key Electrical Characteristics:
The transistor is characterized by its low power consumption and is housed in a compact SOT-23-6 package. Its primary specifications include:
Collector-Emitter Voltage (VCEO): -50 V
Collector Current (IC): -100 mA
Base Resistors (R1/R2): 10 kΩ / 10 kΩ
DC Current Gain (hFE): Ranges from 60 to 250 at specific operating conditions, ensuring sufficient drive capability.
Primary Applications and Usage:
The BCR141W is predominantly used as an interface between low-power microcontrollers or ICs and higher-load components. Its primary function is switching and amplification in a vast array of electronic systems.
Load Switching: Directly driving relays, solenoids, lamps, or LEDs from a microcontroller's GPIO pin.
Line Driver: Used in communication interfaces for signal buffering and level shifting.
Inverter and Amplifier Circuits: Serving as a fundamental building block in logic inversion and small-signal amplification stages.
Consumer and Industrial Electronics: Commonly found in appliances, power management systems, and automotive electronics for controlling various loads.
Application Considerations:
When designing with the BCR141W, several factors must be considered to ensure optimal performance:
1. Current Limiting: The integrated base resistor (R1) limits the base current. The designer must calculate if the resulting base current provides sufficient drive for the desired collector current, using the formula IC = hFE IB.
2. Pull-Down Function: The integrated base-emitter resistor (R2) ensures the transistor turns off reliably by pulling the base to ground when the input is in a high-impedance state, improving noise immunity.
3. Power Dissipation: The total power dissipation of the device (approximately 300 mW) must not be exceeded. This includes the power dissipated in the internal resistors and the transistor junction.
ICGOODFIND: The Infineon BCR141W digital transistor stands out as an exemplary solution for modern, space-constrained designs. Its integrated resistor network significantly enhances design efficiency and system reliability. For engineers seeking to simplify circuitry, reduce board space, and improve production yield without compromising performance, the BCR141W is an optimal choice for interface and driver applications across consumer, industrial, and automotive domains.
Keywords: Digital Transistor, Load Switching, Integrated Resistor Network, SOT-23-6, Microcontroller Interface.
