Patent ID: 7139548
Filing Date: 2006-11-21
Classification: H03B,H03L,H04B

Abstract:
1. A semiconductor integrated circuit device comprising: a demodulation circuit for demodulating a reception signal; a first oscillation circuit for generating a signal to be combined with the reception signal or an oscillation signal as a base of the signal; a modulation circuit for modulating a transmission signal; a second oscillation circuit for generating a signal to be combined with the transmission signal or an oscillation signal as a base of the signal; a reference oscillation circuit for generating a reference frequency signal which determines the frequency of each of oscillation signals generated by said first and second oscillation circuits; and first and second external terminals provided in correspondence with said reference oscillation circuit, wherein said reference oscillation circuit includes a transistor of which control terminal is connected to said first external terminal, a capacitor element connected between said first and second external terminals, and a resistive element connected between said second external terminal and a power source voltage terminal, said reference oscillation circuit can oscillate when a part of an output of said transistor is fed back to the control terminal of the transistor, and said second external terminal is set to a predetermined potential or an open state depending on either an oscillator or an electronic part for oscillation for outputting an oscillation signal is connected to said first external terminal.