Symmetric integrated stacked transformer

Abstract

The invention discloses a symmetric integrated stacked transformer. The symmetric integrated stacked transformer comprises a substrate, a first layer of medium, a second layer of medium and a third layer of medium, which are arranged on the substrate from bottom to top in sequence, a latticed shield grid, which is positioned in the first layer of medium, a primary coil, which is positioned in the second layer of medium, and a secondary coil, which is positioned in the third layer of medium, wherein the shield grid is arranged on the lower plane of the first layer of medium; the primary coil is formed by parallel connection of two circles of square micro-strip coils, which are separated with each other and are symmetrical around the axis, and is arranged on the lower plane of the second layer of medium; the secondary coil is formed by series connection of fives circles of square micro-strip coils, which are separated with each other and are symmetrical around the axis, and is arranged on the lower plane of the third layer of medium; the adjacent coils in pairs are crossly connected with each other at the places close to the axis through two connecting lines, one remaining circle of the coil is directly connected at the place close to the axis through the connecting line of the same metal layer, and a center tap of the secondary coil is arranged on the middle point of the coil. The symmetric integrated stacked transformer has the characteristics of good symmetry, high rate of turn and high magnetic induction coefficient.

Description

technical field [0001] The invention belongs to the technical field of radio frequency analog integrated circuits. It relates to a transformer, and more particularly relates to a symmetrical integrated laminated transformer. The invention is mainly applied in the broadband low-noise amplifier or mixer at the front end of the radio frequency receiver to convert the current or voltage of the radio frequency signal. Background technique [0002] Integrated transformers in radio frequency and microwave integrated circuits can be implemented in tiled, interleaved, and stacked types, among which the stacked type has the largest magnetic inductance. Such as literature [1] J.R.Long, "Monolithic transformers for silicon RF IC design", IEEE Journal of Solid-State Circuits, 35(9), pp.1368-1382, 2000 and literature [2] J.J.Zhou, "Monolithic transformers and their application in a differential CMOS RFlow-noise amplifier", IEEE Journal of Solid-State Circuits, 33(12), pp.2020-2027, 1998...

AI Technical Summary

Problems solved by technology

[0003] 1) The induction coil is asymmetrical and is not suitable for use in a symmetrical broadband circuit (such as a broadband fully differential amplifier) ​​to suppress common-mode signals;

[0004] 2) The parasitic capacitance of the induction coil relative to the substrate is large, because the size (or area) of the integrated laminated transformer with a high turns ratio is large (its outer diameter is generally greater than 200 μm), so both the parasitic capacitance and the parasitic resistance Larger (the parasitic capacitance of the secondary coil relative to the substrate is generally greater than 0.1pF, and the parasitic resistance of the secondary coil is generally greater than 20Ω), resulting in a lower resonance frequency (generally lower than 4GHz), which limits the integrated stacking to a certain extent Transformer performance and operating frequency range;

[0005] 3) There is no center tap, so there is only one set of outputs, and the application is limited

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