App Note by Dimitri Danyuk

Linear Integrated Systems headphone amplifier evaluation board is a complete, low-power stereo audio amplifier for high-fidelity line-level output and headphone applications. It consists of Linear Integrated Systems JFETs along with a number of other parts mounted on a circuit board.

Linear Integrated Systems headphone amplifier evaluation board includes the following features:

• Stereo, single ended input and single ended output

• 400 mW output power into 100Ω

• Wide frequency response (10Hz?200kHz; ?1dB)

• Voltage gain 5 (14dB)

• Low distortion (THD+N is less than 1% at 10Hz?20kHz at 5Vrms into 100Ω and less than 0.1% from 10 Hz to 20 kHz at 1Vrms into 100Ω load)

• Short circuit protection

• Pop reduction (slow start) circuit

• Defeatable cross feed circuit

• Volume control

• Overvoltage and reverse polarity power protection

• Audio input and output connections: left and right RCA phono jack inputs, ¼” stereo phone jack output

• External 9V–16V supply input

• External power supply connector: power jack, inside diameter 2.1mm, outside diameter 5.5mm