Accurate, wide range analog sine shaping circuits

Sine shaping functionality is important in many applications. Existing circuit implementations are typically restricted in input voltage or input angular range, limiting their usefulness in real-world applications. In this contribution we introduce resistive source degeneration and transconductance attenuation so that sine shaping circuits can accept an arbitrary input range and achieve high accuracy. We present detailed analysis including accuracy and efficiency of the circuits using approximation with the sum of multiple hyperbolic tangent like functions. We also describe a design methodology that satisfies specific requirements for a sine shaping circuit. The design was verified with two examples in simulation using a BSIM3.3 model and nearly perfect sine function circuit was demonstrated. The applicability of this circuit for a triangle-to-sine converter was also verified using Monte Carlo simulation. Compared to other sine waveform generators this circuit has an extended frequency range and requires the lowest power.