Supertex inc.
Four-Channel
High Voltage Protection T/R Switch
MD0105
Features
►► Up to ±130V input voltage protection
►► Low on resistance - 15Ω typical
►► Fast switching speed
►► Four electrically isolated channels
►► No external supplies needed
Applications
►► Medical ultrasound imaging
►► NDT applications
►► Fast resettable fuses
►► High side switches
►► Data acquisition
General Description
The Supertex 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 15Ω, 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.
Typical Application Circuit
+130V
Logic
Control
and
Signal
Processing
Transmitter
TX
-130V
RX
Receiver
B MD0105 A
T/R Switch
Piezo
Transducers
High Voltage
Switches
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com