Mixer with reduced carrier feedthrough
AssigneeMotorola, Inc.
InventorsMatthew D. Rowley, David E. Bockelman
Life of this patent
Estimating the term…
Abstract
A mixer circuit (100) includes two balanced transmission gate mixers (102, 104). The mixer circuit (100) balances charge injection mechanisms which reduces carrier feedthrough in the preferred embodiment. The inputs signals provided to the second transmission gate mixer (104) are reversed as compared to those provided to the first transmission gate mixer (102). By reversing the forward path through the second transmission gate mixer (104), charge injection parasitics seen by the first transmission gate mixer (102) are canceled by those in the second transmission gate mixer (104).
Claims13
A mixer circuit, comprising:
- a first mixer having an output port, and first and second input ports;
- a second mixer having an output port, and first and second input ports;
- a first input signal coupled to the first input ports of the first and second mixers;
- a second input signal coupled to the second input ports of the first and second mixers;
- the first input signal coupled to the second mixer has a phase shift substantially equal to 180 degrees relative to the first input signal coupled to the first mixer;
- and
- the second input signal coupled to the second mixer has a phase shift substantially equal to 180 degrees relative to the second input signal coupled to the first mixer.
A mixer, comprising:
- a first transmission gate mixer having first and second output terminals;
- a second transmission gate mixer having third and fourth output terminals;
- and
- the first output terminal is coupled to the third output terminal and the second output terminal is coupled to the fourth output terminal.
A transmission gate mixer, comprising:
- a first input port;
- a second input port;
- an output port;
- a first transmission gate having an N gate coupled to a first node of the input first port, a P gate coupled to a second node of the first input port, a first drain/source node coupled to a first node of the second input port, and a second drain/source node coupled a first node of the output port;
- a second transmission gate having an N gate coupled to the second node of the first input port, a P gate coupled to the first node of the first input port, a first drain/source node coupled to a second node of the second input port, and a second drain/source node coupled to the first node of the output port;
- a third transmission gate having an N gate coupled to the second node of the first input port, a P gate coupled to the first node of the first input port, a first drain/source node coupled to the first node of the second input port, and a second drain/source node coupled to the second node of the output port;
- and
- a fourth transmission gate having an N gate coupled to the first node of the first input port, a P gate coupled to the second node of the first input port, a first drain/source node coupled to the second node of the second input port, and a second drain/source node coupled to the second node of the output port.
Dependencies are inferred from the claim text.