The 2SK904 is an N-channel silicon junction field-effect transistor (JFET) manufactured by Fuji Electric. It is designed for low-noise amplifier applications and analog switching. Its low input capacitance and high transconductance make it suitable for sensitive signal amplification.

Applications

• Low-noise amplifiers (LNA) in radio receivers
• Audio preamplifiers
• Analog switches
• Impedance converters
• Voltage-controlled resistors

Features

• N-channel JFET
• Low noise figure
• High transconductance
• Low input capacitance
• High input impedance

Benefits

• Excellent signal amplification with minimal added noise
• High sensitivity to input signals
• Reduced signal loading due to high input impedance
• Improved frequency response due to low input capacitance
• Enhanced circuit performance in sensitive applications

Additional Details

The 2SK904 JFET requires a negative gate-source voltage (VGS) to control the drain current (ID). The specific operating point and biasing network are crucial for optimal performance. The datasheet provides detailed information on the drain current versus gate-source voltage characteristics, as well as the noise figure and transconductance parameters at various frequencies. Proper shielding and grounding techniques are essential in low-noise amplifier circuits to minimize external interference and maintain a high signal-to-noise ratio. Careful consideration of the load impedance is also important for maximizing voltage gain and overall amplifier performance. The device is commonly packaged in a through-hole format for easy mounting. The datasheet also lists maximum ratings for voltages, currents and power dissipation which should be adhered to for reliable operation.