Infineon BUZ30A Power MOSFET: Datasheet, Pinout, and Application Circuits

The Infineon BUZ30A stands as a classic and widely used N-channel enhancement-mode power MOSFET. It has established a strong reputation for its robustness, high switching speed, and ease of use in a multitude of power electronic applications. This article provides a detailed overview of its datasheet specifications, pinout configuration, and common circuit implementations.

Datasheet Overview and Key Specifications

The BUZ30A is designed to handle significant power levels while offering efficient control. Its key electrical characteristics, as defined in its datasheet, make it suitable for switching applications.

Absolute Maximum Ratings:

Drain-Source Voltage (V_DS): 400 V

Drain Current (I_D): 3.5 A (continuous) at T_case = 25°C

Pulse Drain Current (I_DM): 14 A

Gate-Source Voltage (V_GS): ±20 V

Total Power Dissipation (P_tot): 75 W at T_case = 25°C

Electrical Characteristics (Typ. at T_j = 25°C):

Drain-Source On-Resistance (R_DS(on)): 1.5 Ω (max. at I_D = 1.5 A, V_GS = 10 V)

This is a crucial parameter, as a lower R_DS(on) translates to lower conduction losses and higher efficiency.

Gate Threshold Voltage (V_GS(th)): 2 - 4 V

The minimum voltage required to form the conductive channel.

Input Capacitance (C_iss): 250 pF

Turn-On Delay Time (t_d(on)): 14 ns

Rise Time (t_r): 60 ns

The fast switching speeds are essential for high-frequency operation, reducing switching losses.

Pinout Configuration

The BUZ30A is commonly available in the TO-220AB package, a through-hole package renowned for its good thermal performance, enabled by the metal tab which can be attached to a heatsink.

The pinout is standard for a TO-220 transistor:

1. Gate (G): This is the control pin. The voltage applied between the Gate and Source terminals controls the flow of current between the Drain and Source.

2. Drain (D): This is the load pin. It is connected to the higher voltage of the circuit being switched.

3. Source (S): This is the common or ground reference pin. It is typically connected to the circuit ground.

Important Note: The metal tab of the TO-220 package is internally connected to the Source (S) pin. This must be considered when mounting the MOSFET to a heatsink to avoid accidental short circuits.

Application Circuits

The BUZ30A's high voltage and current ratings make it a versatile component in both linear and switching power systems.

1. Low-Side Switch Circuit:

This is the most common application. The MOSFET is placed between the load and ground. A microcontroller or logic circuit can easily drive the gate (with a suitable gate resistor, e.g., 10-100Ω) to turn the load (like a DC motor, solenoid, or lamp) ON and OFF.

Operation: A voltage (typically +10V to +12V) applied to the gate turns the MOSFET ON, completing the circuit and powering the load. Removing the gate voltage turns it OFF.

2. High-Side Switch Circuit:

Here, the MOSFET is placed between the power supply (V_CC) and the load. This configuration is often used for safety reasons or specific circuit topologies but requires a gate driver circuit capable of supplying a voltage higher than V_CC to fully enhance the MOSFET.

3. PWM Motor Speed Control:

By rapidly switching the BUZ30A ON and OFF using a Pulse Width Modulation (PWM) signal from a microcontroller, the average power delivered to a DC motor can be controlled. This allows for precise and efficient speed regulation. A flyback diode is critical in this and any inductive load circuit to protect the MOSFET from voltage spikes generated when the current is switched off.

4. Simple Switched Mode Power Supply (SMPS):

The BUZ30A can serve as the main switching element in off-line flyback or forward converter designs for low-to-medium power AC/DC or DC/DC power supplies. Its 400V V_DS rating is well-suited for rectified mains voltage applications.

ICGOODFIND

The Infineon BUZ30A remains a highly reliable and effective choice for designers working on projects requiring robust high-voltage switching. Its excellent balance of voltage handling, current capability, and fast switching performance ensures its continued relevance in power supply design, motor control, and general power switching applications. When selecting a modern equivalent, always consult the latest datasheets for performance comparisons.

Keywords:

Power MOSFET

Switching

TO-220

Drain-Source On-Resistance

Gate Threshold Voltage