MA44781

Overview

The MA44781 is a dual pair anti-parallel non-magnetic PIN diode designed for MRI passive switching applications. It operates within an operating temperature range of -55°C to +125°C and features a junction temperature rating of +175°C. The device has a minimum breakdown voltage of 60 V at 10 µA reverse current. Electrical specifications include a forward voltage between 0.500 V and 0.780 V at 20 µA, with a delta forward voltage tolerance of +/- 30 mV. Junction capacitance per diode ranges from 0.15 pF to 0.50 pF at 1 MHz and -6.0 V reverse bias. Total capacitance at 0 V reverse bias spans 1.5 pF to 3.5 pF.

Feature Summary

• Non-magnetic surface mount package construction
• Anti-parallel self-bias arrangement for efficient RF power handling
• SPC process for superior parametric repeatability

Applications

• MRI passive switching
• Tuning and de-tuning resonant MRI tank circuits

Procurement Notes

Verify the specific datasheet revision (Rev. V5) matches your design requirements before procurement. Confirm that the ODS-1134 package style aligns with your PCB footprint constraints. Ensure ESD control techniques are implemented during handling due to static sensitivity. Check RoHS compliance status against current regulatory standards in your target market. Validate thermal dissipation limits under your specific operating conditions.

Selection Notes

Select this component when non-magnetic properties are critical for MRI environments. The dual pair configuration supports high Q R-C network behavior for small signals. Evaluate the 60 V breakdown voltage against peak RF signal levels. Consider the 2 A forward current rating per diode pair for power handling needs. Verify compatibility with 260°C reflow soldering processes.

Part Context

The MA44781 belongs to MACOM's specialized line of silicon PIN diodes intended for medical imaging systems. It utilizes Case Style 1134 packaging sealed with non-conductive epoxy resin. This series addresses the unique electromagnetic interference challenges found in magnetic resonance imaging equipment.

Replacement Considerations

No public confirmed substitute part numbers are available in the documentation.

FAQ

What is the maximum operating temperature for the MA44781?

The maximum operating temperature is +125°C.

How does the device function in MRI applications?

It acts as a passive switch where PIN diodes form a high Q R-C network under small signals and behave as an effective passive rectifier or short circuit under high RF signals to tune and de-tune the resonant MRI tank circuit.

What is the total capacitance specification?

The total capacitance ranges from 1.5 pF to 3.5 pF at 0 V reverse bias.