BLF175,112

Overview

The BLF175 is a silicon N-channel enhancement mode vertical D-MOS transistor designed for large signal amplifier applications in the HF/VHF frequency range. It features a 4-lead SOT123A flange package with a ceramic cap and gold metallization. Key electrical parameters include a drain-source voltage of 125 V, total power dissipation of 68 W at 25 °C mounting base temperature, and a junction temperature limit of 200 °C. In Class-A operation at 28 MHz, it delivers 8 W PEP output with over 24 dB gain. Class-AB performance at 28 MHz provides 30 W PEP with typical 24 dB gain and 40% efficiency. CW Class-B operation at 108 MHz yields 30 W output with typical 20 dB gain and 65% efficiency.

Feature Summary

• High power gain and low intermodulation distortion suitable for linear amplification
• Robust construction withstands full load mismatch conditions
• Gold metallization ensures excellent reliability and thermal stability

Applications

• Large signal amplifier applications in the HF/VHF frequency range
• SSB transmitter stages operating in Class-A or Class-AB modes
• CW transmitter stages operating in Class-B mode

Procurement Notes

Verify the specific gate-source voltage group letter marking on the component body against the required matching pair specifications before integration. Ensure that handling procedures strictly adhere to anti-static precautions as outlined in Philips specs SNW-EQ-608 and SNW-FQ-302A/B due to electrostatic sensitivity during transport.

Selection Notes

Select this component for designs requiring high ruggedness and reliable performance in HF/VHF bands. Consider the thermal resistance from junction to mounting base (2.6 K/W) when designing heatsinking solutions. Match pairs are available based on gate-source voltage groups indicated by alphanumeric codes on the package for balanced differential circuits.

Part Context

The BLF175 belongs to the Ampleon portfolio of RF power transistors, originally developed under Philips Semiconductors. It utilizes a vertical D-MOS technology optimized for high power density. The device is housed in the SOT123A flange package, which facilitates direct mounting to heatsinks via two mounting holes, ensuring efficient thermal management for continuous wave and peak envelope power operations.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source documentation.