Bidirectional Mosfet Switch Board

Introducing our next-generation Bidirectional MOSFET Switch, completely redesigned from the ground up for ultra-fast, high-frequency AC circuit experimentation. This new revision focuses on minimizing gate-loop inductance, incorporates a brand-new high-speed gate driver, and adds several practical features for demanding laboratory and research applications. Here’s why this upgraded bidirectional switch is an essential tool for advanced experimentation:

• Bidirectional Current Blocking: Using two MOSFETs in a back-to-back (common-source) configuration, the switch blocks current flow in both directions when turned off. This overcomes the body-diode limitation of single MOSFETs and makes the board ideal for AC systems where current alternates direction.
   
• Ultra-Fast Switching: The new gate driver enables switching transitions just above 10 ns (MOSFET- and load-dependent). This allows rapid connection and disconnection of inductors, capacitors, and other reactive components, and precise manipulation of tank and resonance circuits.
   
• Low Gate-Loop Inductance Layout: The PCB layout has been fully reworked to minimize gate-loop inductance, resulting in cleaner edges, reduced ringing, and more stable operation at high frequencies.
   
• Ideal for Resonance Circuits: True bidirectional current blocking makes this switch indispensable in resonant AC systems, where current must flow alternately in both directions without distortion.
   
• Robust Isolated Driver System: Like our standard MOSFET Switch Board, this model uses isolated gate drivers powered by an onboard DC-DC converter. This allows the MOSFET pair to operate at up to 2300 V potential difference relative to the control electronics.
   
• High-Side or Low-Side Switching: The flexible topology allows the board to be used in both high-side and low-side switching configurations, depending on your circuit requirements.
   
• 3.3V & 5V Logic Compatible: The input stage supports both 3.3 V and 5 V logic signals, enabling direct connection to microcontrollers for programmable and automated switching control.
   
• Selectable 50-Ohm Input Termination: A switchable 50 ohm impedance-matching resistor is included on the input, which is highly beneficial for clean signal integrity when operating at high frequencies with standard signal generators and coaxial cabling.
   
• Built-In Fuse Protection: An onboard fuse provides additional protection in the event of overcurrent or fault conditions, helping to safeguard both the MOSFETs and the gate driver circuitry.
   
• Fan Support for High-Frequency Operation: The board provides 12 V fan output via two XH2.54 connectors as well as a 2-port screw terminal, allowing connection of virtually any fan type for MOSFET cooling. For prolonged operation above 1 MHz, we strongly recommend active airflow directed at the board to prevent thermal shutdown.
   
• High-Frequency Capability: While the achievable speed depends on MOSFET gate capacitance and load conditions, the board comfortably supports frequencies above 1 MHz and has been tested at 3 MHz and beyond with suitable devices.
   
• User-Friendly High-Current Connections: Heavy-duty screw terminals rated for high current and AWG 10 wire ensure secure, low-loss connections for demanding AC switching applications.
   
• BNC Input for Convenience: A dedicated BNC connector provides a clean, reliable connection to function generators and laboratory signal sources.
   
• Input Signal Compatibility: Designed for square-wave input signals in the 3.3 V to 5 V range (into 50 ohm when selected). Negative input voltages must be avoided to protect the gate driver.

Whether you are modifying resonant tank circuits or performing advanced high-frequency AC switching experiments, this next-generation bidirectional MOSFET switch delivers exceptional performance, robustness, and precision.

Technical Specification:

Datasheets for the selectable MOSFETs can be found here: TK125N60Z1—G3R60MT07D—G3R160MT12D—SCTW40N120G2V—MSC035SMA170B

This product includes two heat sinks for TO-247-sized MOSFETs and a BNC to hookup wire adapter for easy connection to a Microcontroller Unit (MCU).