MD0105 is a high voltage current limiting protection device. It is designed to protect a low noise receiver from the high voltage transmit pulses in ultrasound applications and is commonly referred to as a T/R (transmit and receive) switch.

The MD0105 can be considered as a normally closed switch with a typical switch resistance of 15O, allowing small signals to pass. Once the voltage drop across the two terminals exceeds a nominal value of ±2.0V, the device will start to turn off. In the off state, the MD0105 can withstand up to ±130V across its terminals. A small amount of current, typically 200µA, is allowed to flow through.

The MD0105 is not limited to just ultrasound applications. It can also be used for resettable fuses to protect power lines, output short circuit protection, and data acquisition. The MD0105 is available in an 18-Lead 5x5mm DFN package as a four-channel device.