BLF542,112

Overview

The BLF542,112 is a UHF power MOS transistor manufactured by Ampleon USA Inc. It is an N-channel enhancement mode vertical D-MOS device housed in a 6-lead SOT171A flange package with a ceramic cap. The component operates at a drain-source voltage of up to 65 V and dissipates 20 W of total power. In Class-B operation at 500 MHz with a 28 V supply, it delivers 5 W of output power with a gain exceeding 13 dB and drain efficiency greater than 50%. Key electrical characteristics include a breakdown voltage of 65 V, a threshold voltage range of 2.0 V to 4.5 V, and a thermal resistance from junction to mounting base of 8.8 K/W.

Feature Summary

• High power gain suitable for broadband UHF applications
• Robust ruggedness capable of withstanding full load mismatch (VSWR 50:1)
• Excellent reliability ensured by gold metallization
• Easy power control with good thermal stability

Applications

• Large signal amplifier applications in the UHF frequency range
• Broadband RF power amplification
• Class-B linear amplification circuits

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current catalog to ensure compatibility with required gate-source voltage groupings. Confirm that the SOT171A package dimensions match the intended PCB footprint and mounting hole specifications. Check for RoHS compliance status if environmental regulations apply to the final assembly. Ensure handling procedures account for the beryllium oxide content within the ceramic substrate.

Selection Notes

Select this component for designs requiring high gain and ruggedness in the UHF band. Evaluate the thermal management requirements based on the 8.8 K/W junction-to-base resistance. Consider the gate-source threshold voltage grouping (A-Z) to match biasing networks. Verify that the 65 V drain-source breakdown voltage provides sufficient margin for the target operating voltage of 28 V under transient conditions.

Part Context

The BLF542 belongs to the family of UHF power MOS transistors designed for robust performance in demanding RF environments. Originally developed under Philips Semiconductors, production and branding transitioned to Ampleon following the spin-off in December 2015. This device represents a legacy specification maintained for compatibility in existing UHF broadcast and industrial systems requiring reliable large-signal amplification.

Replacement Considerations

Direct replacements are not explicitly listed in the provided documentation. Engineers should evaluate other Ampleon UHF LDMOS or D-MOS transistors with similar SOT171A packaging, voltage ratings, and power dissipation capabilities. Cross-referencing pinouts and thermal characteristics is essential when substituting with devices from other manufacturers.