MRF581

Overview

The MRF581 is a discontinued NPN silicon RF power transistor manufactured by Microsemi Corporation. Designed for high-frequency applications, it operates with a collector-emitter breakdown voltage of 15V and supports a maximum continuous collector current of 200mA. The device delivers a maximum power output of 1.25W at frequencies up to 5GHz. It features a transition frequency of 5GHz and exhibits a noise figure between 2dB and 3dB at 500MHz. DC current gain ranges from 13dB to 15.5dB. The component is housed in an 8-SOIC surface-mount package.

Feature Summary

• High-frequency operation capability up to 5GHz
• Low noise performance suitable for sensitive RF stages
• Surface-mount packaging for automated assembly

Applications

• RF amplifier stages in communication systems
• Test and measurement equipment front-ends
• Wireless infrastructure components

Procurement Notes

This component is officially listed as obsolete by the manufacturer. Procurement must rely on secondary market distributors or surplus inventory holders. Verify lot codes and storage history carefully due to potential age-related degradation. No new production units are available directly from Microchip/Microsemi.

Selection Notes

Engineers should evaluate equivalent active parts from current portfolios or alternative manufacturers offering similar 15V, 5GHz specifications. Consider thermal management requirements for the SOIC package when designing replacement circuits. Verify pin compatibility if substituting into existing footprints.

Part Context

The MRF581 belongs to the legacy Microsemi RF transistor lineup. It was designed before the company's acquisition by Microchip Technology. Current product catalogs focus on newer generations of RF devices with enhanced efficiency and integration levels.

Replacement Considerations

Public confirmed substitute part numbers: MRF5812G.