BF991,215

Overview

The BF991 is an N-channel dual-gate depletion-type MOS-FET in a SOT143 microminiature package. It features integrated back-to-back diodes between gates and source for surge protection. Key electrical parameters include a drain-source voltage of 20 V, a drain current of 20 mA, and total power dissipation of 200 mW up to 60 °C. The device exhibits a transfer admittance of 14 mS at 1 kHz and a noise figure of 1.2 dB at 200 MHz.

Feature Summary

• Dual-gate architecture with interconnected source and substrate
• Integrated back-to-back diodes protect against excessive input voltage surges
• Depletion-type field-effect transistor design

Applications

• VHF television tuners
• FM tuners
• Professional communication equipment

Procurement Notes

Verify the specific revision status (Rev. 03) against the latest NXP documentation before finalizing designs. Confirm that the SOT143 package dimensions and pinout align with the target PCB footprint requirements. Ensure thermal management strategies account for the specified junction-to-ambient resistance and derating curves under expected operating temperatures.

Selection Notes

Select this component for VHF frequency applications requiring low noise figures and high gain stability. The dual-gate configuration allows for independent control of input impedance and gain, making it suitable for tuner stages. Consider the 20 V drain-source voltage limit when designing biasing circuits for RF signal amplification.

Part Context

This part is an N-channel dual-gate MOS-FET designed for RF front-end applications. It belongs to the category of depletion-mode field-effect transistors used in analog signal processing. The SOT143 package provides a compact form factor suitable for space-constrained consumer electronics and professional communication hardware.

Replacement Considerations

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