Single-Ended LNA Active Balun for Second-Order Linearity
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Solution Overview
Problem
Current Low Noise Amplifiers (LNAs) with single-ended outputs face challenges in reducing second-order nonlinearity and require bulky components, leading to increased complexity and power consumption in multi-mode and multi-band transceivers.
Innovation Solution
A single-ended low noise amplifier with integrated active balun functionality is designed to generate a differential output, utilizing a cascaded push-pull stage configuration with MOSFETs to minimize additional noise and current consumption while maintaining low noise figure and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If single-ended LNAs with single-ended outputs are used to save input balls and chip area, then device area is reduced, but second-order nonlinearity increases and requires bulky blocking capacitors
Solution Approach 1:
The single-ended LNA output is segmented into two differential signals using a passive transformer, creating a differential output structure that inherently reduces second-order nonlinearity while maintaining the single-ended input simplicity
Solution Approach 2:
A passive transformer is introduced as an intermediary component to convert the single-ended output signal into a differential signal, enabling the system to benefit from differential signaling properties without requiring a fully differential LNA architecture
2Device complexity
If single balance mixers are used with single-ended LNAs, then device complexity is reduced, but second-order nonlinearity increases requiring complex mixer calibration
Solution Approach 1:
The output signal is segmented into differential components that can be directly fed to double balance mixers, which inherently suppress second-order nonlinearity and eliminate the need for complex calibration procedures
3Object-generated harmful factors
If fully differential LNAs are used to suppress common mode noise and reduce second-order nonlinearity, then noise performance is improved, but device complexity and power consumption increase
Solution Approach 1:
A passive transformer serves as an intermediary that converts single-ended output to differential output, enabling the system to achieve differential signaling benefits for common mode noise suppression without the complexity of a fully differential LNA architecture
Solution Approach 2:
The circuit dynamically converts between single-ended and differential signal modes using the transformer, allowing the system to adapt its output configuration based on the mixing requirements while maintaining simplified input architecture
4Object-generated harmful factors
If passive transformers are used to convert single-ended to differential output, then second-order nonlinearity is reduced, but device area and component size increase
Solution Approach 1:
The transformer is segmented into a planar integrated structure that can be fabricated on-chip, reducing the area compared to traditional bulky discrete transformers while maintaining the signal conversion functionality
Solution Approach 2:
The traditional mechanical/discrete transformer structure is replaced with an integrated planar transformer design that uses electromagnetic coupling between planar windings, significantly reducing the overall component size and area
Data Source
AI summary
Embodiments provide an amplification circuit, an apparatus for amplifying, a low noise amplifier, a radio receiver, a mobile terminal, a base station, and a method for amplifying. An amplification circuit for amplifying a radio signal comprises a first amplification stage configured to amplify an input signal, Vin(t), to obtain an intermediate signal. The amplification circuit further comprises a cascoding circuit configured to amplify the intermediate signal to obtain a first output signal Voutn(t). The amplification circuit further comprises a second amplification stage configured to amplify the intermediate signal to obtain a second output signal, Voutp(t).