Topology for a single ended input dual balanced mixer
First Claim
1. A mixer circuit for generating an IF output responsive to an RF input and a LO drive source, comprising:
- a mixer core having a doubly balanced mixer including a first differentially coupled transistor pair and a second differentially coupled transistor pair;
an RF input circuit coupled to the mixer core, the RF input circuit comprising;
a first inductor having a first terminal coupled to receive an RF input signal and a second terminal;
a biasing resistor having a first terminal coupled to the second terminal of the first inductor and a second terminal coupled to a first bias voltage;
a first input transistor having a first terminal coupled to the second terminal of the first inductor, a second terminal, and a third terminal;
a second inductor having a first terminal coupled to the second terminal of the first input transistor and to the first differentially coupled transistor pair, the second inductor also having a second terminal coupled to a ground potential;
a supply resistor having a first terminal coupled to the third terminal of the first input transistor and a second terminal coupled to a supply potential;
a first capacitor having a first terminal also coupled to the third terminal of the first input transistor and a second terminal coupled to the second differentially coupled transistor pair; and
a third inductor having a first terminal coupled to the second terminal of the first capacitor and a second terminal coupled to the ground potential.
5 Assignments
0 Petitions
Accused Products
Abstract
The mixer circuit is a singled ended input to a double balanced high dynamic range mixer with only two base-emitter junctions across the supply. It provides for the use of bondwires to off chip ground as DC block and DC feed elements. The single ended input and differential output balanced mixer is well suited for the input stage of an integrated radio receiver—off chip circuitry is usually single ended, but on chip circuits are usually differential. No off chip differential RF circuits or baluns are required which reduces off chip component count and improves radio performance. The mixer circuit has lower LO drive requirements because of the DC coupled LO port. This results in better radio performance and a smaller die area because of the DC coupled IF port.
-
Citations
36 Claims
-
1. A mixer circuit for generating an IF output responsive to an RF input and a LO drive source, comprising:
-
a mixer core having a doubly balanced mixer including a first differentially coupled transistor pair and a second differentially coupled transistor pair; an RF input circuit coupled to the mixer core, the RF input circuit comprising; a first inductor having a first terminal coupled to receive an RF input signal and a second terminal; a biasing resistor having a first terminal coupled to the second terminal of the first inductor and a second terminal coupled to a first bias voltage; a first input transistor having a first terminal coupled to the second terminal of the first inductor, a second terminal, and a third terminal; a second inductor having a first terminal coupled to the second terminal of the first input transistor and to the first differentially coupled transistor pair, the second inductor also having a second terminal coupled to a ground potential; a supply resistor having a first terminal coupled to the third terminal of the first input transistor and a second terminal coupled to a supply potential; a first capacitor having a first terminal also coupled to the third terminal of the first input transistor and a second terminal coupled to the second differentially coupled transistor pair; and a third inductor having a first terminal coupled to the second terminal of the first capacitor and a second terminal coupled to the ground potential. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A mixer circuit for generating an IF output responsive to an RF input and a LO drive source, comprising:
-
a mixer core having a doubly balanced mixer including a first differentially coupled transistor pair and a second differentially coupled transistor pair, the mixer core coupled to receive a LO drive signal, the LO drive signal having a plurality of harmonics; a low noise RF input circuit coupled to the mixer core through a folded cascode circuit, the low noise RF input circuit coupled to receive an RF input signal, wherein the folded cascode circuit further isolates the low noise RF input circuit from the LO drive signal and the plurality of harmonics. - View Dependent Claims (7, 8, 9, 10, 11, 12, 14, 15, 16, 17)
-
-
13. A quadrature mixer circuit for generating a quadrature IF output responsive to an RF input and a quadrature pair of LO drive signals, comprising:
-
a mixer core having a first doubly balanced mixer including a first differentially coupled transistor pair and a second differentially coupled transistor pair and a second doubly balanced mixer including a third differentially coupled transistor pair and a fourth differentially coupled transistor pair; an RF input circuit coupled to the mixer core, the RF input circuit comprising; an input inductor having a first terminal coupled to receive an RF input signal and a second terminal; a biasing resistor having a first terminal coupled to the second terminal of the input inductor and a second terminal coupled to a first bias voltage; a first input transistor having a base terminal coupled to the second terminal of the input inductor, an emitter terminal, and a collector terminal; a second inductor having a first terminal coupled to the emitter of the first input transistor and to the first differentially coupled transistor pair and to the third differentially coupled transistor pair, the second inductor also having a second terminal coupled to a ground potential; a supply resistor having a first terminal coupled to the collector of the first input transistor and a second terminal coupled to a supply potential; a first capacitor having a first terminal also coupled to the collector of the first transistor and a second terminal coupled to the second differentially coupled transistor pair and to the fourth differentially coupled transistor pair; and a third inductor having a first terminal coupled to the second terminal of the first capacitor and a second terminal coupled to the ground potential. - View Dependent Claims (19, 20, 21, 22)
-
-
18. A quadrature mixer circuit for generating a quadrature IF output responsive to an RF input and a quadrature pair of LO drive signals, comprising:
-
a mixer core having a first doubly balanced mixer including a first differentially coupled transistor pair and a second differentially coupled transistor pair and having a second doubly balanced mixer including a third differentially coupled transistor pair and a fourth differentially coupled transistor pair;
the mixer core coupled to receive a quadrature LO drive signal, the quadrature LO drive signal having a plurality of harmonics;a low noise RF input circuit coupled to the mixer core through a folded cascode circuit, the low noise RF input circuit coupled to receive an RF input signal, wherein the folded cascode circuit further isolates the low noise RF input circuit from the quadrature LO drive signal and the plurality of harmonics, a first cascode capacitor, a first terminal of the first cascode capacitor coupled to an emitter terminal of a first cascode transistor and a second node of the first cascode capacitor coupled to base terminals of the first cascode transistor and a second cascode transistor, a second cascode capacitor, a first terminal of the second cascode capacitor coupled to the base terminals of the first cascode transistor and the second cascode transistor and a second node of the second cascode capacitor coupled to an emitter terminal of the second cascode transistor. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
-
-
32. A mixer circuit for generating an IF output responsive to an RF input and a LO drive source, comprising:
-
a mixer core having a doubly balanced mixer including a first differentially coupled transistor pair and a second differentially coupled transistor pair, the mixer core coupled to receive a LO drive signal, the LO drive signal having a plurality of harmonics; a low noise single ended RF input circuit coupled to the mixer core through a cascode circuit, the low noise single ended RF input circuit coupled to receive an RF input signal, wherein the cascode circuit further isolates the low noise single ended RF input circuit from the LO drive signal and the plurality of harmonics, the low noise single ended RF circuit including means for providing an input impedance and means for splitting a phase of the RF input signal. - View Dependent Claims (33, 34, 35, 36)
-
Specification