Fast Non-Magnetic Anti-Parallel Protection Diodes

The MADP-009989-1443W0 non-magnetic antiparallel diode was designed to protect MRI receivers from high RF energy fields including long RF pulses and RF spike pulses present in most MRI machines. This diode acts as a passive protector (limiter) for the MRI receiver. No forward bias voltage is required to turn on the diode. It is self-biased by the RF transmitter pulse power. A switch driver is not needed for this receiver protection application. Receiver protector diodes appear directly across the input port of the receiver. They are connected in anti-parallel pairs to limit the RF carrier excursion in both polarities. They must, therefore, exhibit extremely low insertion loss, both in the “on” state (high power present) and the “off” state (receiver power The anti-parallel packaging option eliminates the worry of incorrectly polarized diodes when devices are placed onto the PCB and decreases parasitic capacitance and inductance associated with single packaged diodes.