BF1105WR,135

Overview

The BF1105WR,135 is an N-channel dual-gate MOS-FET in the SOT343R package. Key electrical parameters include a drain-source voltage of 7 V, a drain current of 30 mA, and total power dissipation of 200 mW. The forward transfer admittance ranges from 25 to 31 mS, with an input capacitance at gate 1 of 2.2 to 2.7 pF. Reverse transfer capacitance is 25 to 40 fF at 1 MHz. The noise figure is 1.7 to 2.5 dB at 800 MHz.

Feature Summary

• Dual-gate architecture providing low noise gain controlled amplifier performance up to 1 GHz.
• Integrated self-biasing circuit ensures good cross-modulation performance during AGC and DC stabilization.
• Internal diodes between gates and source protect against excessive input voltage surges.

Applications

• Television tuners
• Professional communications equipment

Procurement Notes

Verify the specific ordering suffix

Selection Notes

Select this component for designs requiring a dual-gate RF MOSFET with integrated self-biasing. It supports 5 V supply operation suitable for VHF and UHF bands. Ensure the application requires the specific SOT343R package footprint and pinout configuration defined in the datasheet.

Part Context

This device belongs to the BF1105 family of N-channel dual-gate MOS-FETs. Variants include BF1105 (SOT143B) and BF1105R (SOT143R). All share identical electrical characteristics but differ in physical encapsulation and pin arrangement.

Replacement Considerations

Direct substitutes within the same electrical specification are BF1105 and BF1105R. Note that these alternatives utilize different packages (SOT143B and SOT143R respectively), requiring PCB layout adjustments for pin compatibility.

FAQ

What is the function of the internal diodes?

Internal diodes between the gates and source protect the device against excessive input voltage surges.

How does the self-biasing circuit benefit the design?

It ensures good cross-modulation performance during Automatic Gain Control (AGC) and provides good DC stabilization.