High frequency divider circuits and methods

A divider circuit comprising:

• a differential circuit having first and second inputs to receive a first differential signal, and first and second differential output nodes, wherein the differential circuit is coupled to a first bias current generator;
• and
• a cross-coupled circuit having a first control terminal coupled to a second output of the cross-coupled circuit and the first differential output node and a second control terminal coupled to a first output of the cross coupled circuit and the second differential output node, wherein the cross-coupled circuit is coupled to a second bias current generator,
• wherein the differential circuit is coupled to a first transistor having a control terminal for receiving a signal to be divided, and wherein the first bias current generator is coupled to the differential circuit through the first transistor, and
• wherein the cross-coupled circuit is coupled to a second transistor having a control terminal for receiving the complement of the signal to be divided, and wherein the second bias current generator is coupled to the differential circuit through the second transistor.

A divider circuit comprising:

• first and second transistors having sources coupled together to form a differential circuit, the first transistor having a first output terminal and the second transistor having a second output terminal;
• first and second cross-coupled transistors having sources coupled together, the first cross-coupled transistor having a first output terminal coupled to the first output terminal of the first transistor and the second cross-coupled transistor having a second output terminal coupled to the second output terminal of the second transistor;
• a first resistor coupled between the first output terminal of the first transistor and a supply terminal, the first resistor having a first resistance value;
• a second resistor coupled between the second output terminal of the second transistor and the supply terminal, the second resistor having a second resistance value approximately equal to the first resistance value;
• a third transistor having a control terminal coupled to a signal to be divided and a first terminal coupled to the sources of the first and second transistors, wherein the third transistor is coupled to a first bias generator that generates first bias current in the first and second transistors;
• and
• a fourth transistor having an control terminal coupled to a complement of the signal to be divided and a first terminal coupled to the sources of the cross-coupled transistors, wherein the fourth transistor is coupled to a second bias generator that generates second bias current in the first and second cross-coupled transistors.

A divider circuit comprising:

• a differential circuit having first and second inputs to receive a first differential signal and first and second differential output nodes;
• a cross-coupled circuit having a first control terminal coupled to a second output of the cross-coupled circuit and the first differential output node and a second control terminal coupled to a first output of the cross coupled circuit and the second differential output node;
• a first transistor coupled to the differential circuit;
• a second transistor coupled to the cross coupled circuit;
• first bias means for biasing the differential circuit with a first bias current coupled to the differential circuit through the first transistor;
• and
• second bias means for biasing the cross-coupled circuit with a second bias current coupled to the cross-coupled circuit through the second transistor.

A method of dividing a signal comprising:

• receiving a first input signal to be divided on a frequency control input of a first transistor;
• receiving a complement of the first input signal on a frequency control input of a second transistor;
• coupling the first input signal to a differential circuit;
• coupling the complement of the first input signal to a cross-coupled circuit;
• coupling a first bias current through the first transistor to the differential circuit using a first bias current generator;
• coupling a second bias current through the second transistor to the cross-coupled circuit using a second bias current generator;
• operating the differential circuit using the first bias current;
• and
• operating the cross-coupled circuit using the second bias current.