THE CA-3020 INTEGRATED CIRCUIT

The operation of the CA-3020 can best be understood by considering its functional block diagram, shown in Fig 20.12. Transistor Q1 with the external 5.1 KΩ resistor constitutes an emitter-follower to provide an input resistance of 55 KΩ. The output of the buffer amplifier drives a differential amplifier which, with one base grounded (for a.c.), performs a phase splitting function to provide two signals 180° out of phase with each other at A and B, see Fig. 20.14. The voltage regulator, with the three diodes constructed from transistor base-emitter junctions and resistor R11, provides the differential amplifier with a collector supply voltage of about 2.1 volts at C and a base supply voltage of about 1.4 V at D. ...

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