The VCO requires one external capacitor C1 and one or two external resistors (R1 or R1 and R2). Resistor R1 and capacitor C1 determine the frequency range of the VCO and resistor R2 enables the VCO to have a frequency offset if required. The high input impedance (1012) of the VCO simplifies the design of low pass filters by permitting the designer a wide choice of resistorto-capacitor ratios. In order not to load the low-pass filter, a source-follower output of the VCO input voltage is provided at terminal 10 (DEMODULATED OUTPUT). If this terminal is used, a load resistor (RS) of 10k or more should be connected from this terminal to VSS. If unused this terminal should be left open. The VCO can be connected either directly or through frequency dividers to the comparator input of the phase comparators. A full CMOS logic swing is available at the output of the VCO and allows direct coupling to CMOS frequency dividers such as the Intersil CD4024, CD4018, CD4020, CD4029, and CD4050. One or more CD4018 (Preset Table Divide-By-N Counter) or CD4029 (Presettable Up/Down Counter) or CD4029 (Presettable Divideby-N Counter) or CD4029 (Presettable Up/Down Counter), or CD4059A (Programmable Divide-by "N" Counter), together with the CD4046BMS (Phase-Locked Loop) can be used to build a micropower low-frequency synthesizer. A logic 0 on the INHIBIT input "enables" the VCO and the source follower, while a logic 1 "turns off" both to minimize stand-by power consumption.