Infineon BCR116E6327: A Comprehensive Technical Overview and Application Note
The Infineon BCR116E6327 is a highly integrated, low-voltage PNP digital transistor (also known as a resistor-equipped transistor or RET) designed to replace a single transistor and its discrete base and emitter resistors in one compact SMD package. This integration simplifies circuit design, reduces the component count on a PCB, and enhances overall reliability. It is a cornerstone component for designers seeking efficient switching solutions in space-constrained, high-volume applications.
Technical Overview and Key Features
Housed in a miniature SOT-23-3 package, the BCR116E6327 combines a PNP bipolar junction transistor (BJT) with two internal resistors. This configuration is optimized for direct interfacing with microcontrollers (MCUs) and other digital logic circuits.
Its primary electrical characteristics include:
Integrated Resistors: The device features a monolithic integration of a base resistor (R1 = 4.7 kΩ) and an emitter-base resistor (R2 = 47 kΩ). This eliminates the need for external biasing components.
Low Saturation Voltage: With a collector-emitter saturation voltage (VCE(sat)) typically around 250 mV, the transistor switches efficiently, minimizing power loss in the "on" state.
High Current Gain: The device offers a high DC current gain (hFE), which ensures effective amplification of a small base current to control a larger load current.
Low Trigger Current: It can be switched effectively with very low input currents, making it perfectly suited for direct drive from GPIO pins of microcontrollers that typically source/sink only a few milliamps.
Voltage Ratings: It features a collector-emitter voltage (VCEO) of -50 V and a collector-base voltage (VCBO) of -50 V, making it robust for a wide range of low-power applications.
Application Notes
The BCR116E6327 excels as an interface between a control unit and a load. Its primary function is to act as a low-side switch.
Typical Application Circuit: Driving an Inductive Load (e.g., Relay, Solenoid)
1. The microcontroller's GPIO pin is connected directly to the input pin (the internal base resistor) of the BCR116E6327.
2. The load (e.g., a relay coil) is connected between the positive supply voltage (Vcc) and the collector pin of the transistor.
3. The emitter pin is connected to ground.
4. To protect the transistor from voltage spikes generated when switching off inductive loads, a flyback diode must be placed in reverse bias across the relay coil.
Operation:
When the microcontroller output is set to a logic LOW (0 V), a current flows from the GPIO pin into the base of the PNP transistor, turning it ON. This allows current to flow from Vcc, through the load, through the transistor, and to ground, thereby energizing the load.
When the microcontroller output is set to a logic HIGH (e.g., 3.3V or 5V), the base-emitter junction of the PNP transistor is reverse-biased or has insufficient forward bias, turning the device OFF. This breaks the circuit and de-energizes the load.
Design Considerations:
Load Current: Ensure the collector current (IC) of your load does not exceed the continuous collector current rating of the BCR116E6327 (1000 mA).
Inductive Kickback: Never omit the flyback diode when driving inductive loads to prevent destruction from counter-electromotive force (CEMF).
Heating: While the integrated resistors reduce power dissipation in the control circuit, calculate the power dissipation in the transistor itself (Ptot = VCE IC) to ensure it remains within safe operating limits.
The Infineon BCR116E6327 is an exemplary solution for simplifying digital logic interfacing. By integrating crucial biasing resistors into a single, compact package, it significantly reduces PCB footprint and assembly complexity. Its robustness, defined by its voltage and current ratings, coupled with its ease of use, makes it an ideal choice for designers across consumer electronics, industrial control, and automotive applications where reliable, microcontroller-driven switching is paramount.
Keywords: Digital Transistor, PNP Low-Side Switch, Microcontroller Interface, Integrated Resistors, SOT-23
