Voltage controlled oscillator suitable for complete implementation within a semiconductor integrated circuit

A voltage controlled oscillator (VCO), comprising:

• a single tank circuit;
• a differential amplifier transistor pair having inputs coupled to the tank circuit;
• a first pair of positive feedback networks having a first phase-lead reactance and with one of each of the pair cross-connected to the differential amplifier transistor pair;
• a second pair of positive feedback networks having a second phase-lead reactance and with one of each of the pair cross-connected to the differential amplifier transistor pair;
• a plurality of current-steering transistors;
• and
• a differential input coupled to the plurality of current-steering transistors to control the mixture of positive feedback signals from the first and second pairs of positive feedback networks and the operating frequency of the VCO is controlled in relation to a difference-mode signal on the differential input.