The block diagram of the CA3085 series circuits is shown in Figure 1. Fundamentally, the circuit consists of a frequency compensated error-amplifier which compares an internally generated reference voltage with a sample of the output voltage and controls a series-pass amplifier to regulate the output. The starting circuit assures stable latch-in of the voltage-reference circuitry. The current-limiting portion of the circuit is an optional feature that protects the IC in the event of overload.