Integrated high frequency balanced-to-unbalanced transformers
AssigneeTheta Microelectronics, Inc.
InventorYannis Papananos
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Abstract
Integrated high frequency balanced-to-unbalanced transformers suitable for operation in high frequencies, such as radio frequencies. Embodiments disclosed give consideration to issues related to the layout of the primary and secondary inductors for the minimization of capacitive effects between layers while using a minimal number of metal layers. Two solutions are provided, one having embodiments with a symmetrical primary inductor in a 4-metal layer implementation and one having embodiments with a non-symmetrical primary inductor in a 3-metal layer implementation.
Claims10
An on-chip three-metal layer balanced-to-unbalanced (BALUN) transformer comprising:
- a first winding conductive path formed in a first metal layer defining a multiple turn primary inductor of the BALUN transformer, the first winding conductive path having a first port at one end of the first winding conductive path and a second port at the other end of the first winding conductive path;
- and,
- a second winding conductive path having a plurality of symmetrical winding segments formed in a second metal layer;
- shunts formed in a third metal layer and electrically connecting the winding segments at respective intersections, thereby forming a secondary inductor of the BALUN transformer, the secondary inductor having a third port and a fourth port and further having a center tap connection from a position essentially at the middle of the secondary inductor as a fifth port;
- the secondary inductor conductive path being displaced vertically and horizontally from the first winding conductive path to reduce capacitive coupling between the primary inductor and the secondary inductor while maintaining a sufficient magnetic coupling between the first winding conductive path and the secondary inductor.
An on-chip balanced-to-unbalanced (BALUN) transformer comprising:
- a first winding conductive path formed in a first metal layer defining a multiple turn primary inductor of the BALUN transformer, the first winding conductive path having a first port at one end of the first winding conductive path and a second port at the other end of the first winding conductive path;
- and,
- a second winding conductive path having a plurality of symmetrical winding segments formed in a second metal layer defining a secondary inductor of the BALUN transformer, the secondary inductor having a third port and a fourth port and further having a center tap connection from a position essentially at the middle of the secondary inductor as a fifth port;
- the secondary inductor conductive path being vertically and horizontally displaced from the first winding conductive path to reduce capacitive coupling between the primary inductor and the secondary inductor while maintaining a sufficient magnetic coupling between the first winding conductive path and the secondary inductor.
Dependencies are inferred from the claim text.