The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LS/ALSTTL outputs. The IN74HC4046A phase-locked loop contains three phase comparators, a voltage-controlled oscillator (VCO) and unity gain opamp DEMOUT. The comparators have two common signal inputs, COMPIN, and SIGIN. Input SIGIN and COMPIN can be used directly coupled to large voltage signals, or indirectly coupled (with a series capacitor to small voltage signals). The self-bias circuit adjusts small voltage signals in the linear region of the amplifier. Phase comparator 1 (an exclusive OR gate) provides a digital error signal PC1OUT and maintains 90 degrees phase shift at the center frequency between SIGIN ORDERING INFORMATION