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CXA3068N

Description of Operation (Refer to the Electrical Characteristics Measurement Circuit.)

1) Oscillator circuit

The oscillator circuit is formed with two Colpitts oscillators, and oscillation is provided at the differential

input via an LC resonance circuit including a varicap diode. This is oscillated only by attaching an LC

resonance circuit externally because feedback capacitance, etc. are built in for oscillation.

2) Mixer circuit

This is a double-balance mixer having small leak of local oscillation signal. The RF signal is input to Pins

5 and 6. In normal use, the signal is input to one pin while the other pin is connected to GND via

decoupling capacitor.

3) IF amplifier circuit

The mixer output signal is amplified by the IF amplifier and output to Pin 1. The IF output is emitter-

follower output and output impedance is approximately 50

Ω (480 MHz).

4) PLL oscillation signal output circuit

The output circuit is built in to drive the PLL for tuning. This is emitter-follower output and output

impedance is approximately 50

Ω.