Mixer design - Part VI — Lesson 6

This lesson covers the intricate aspects of mixer design and noise analysis in electronic circuits. It delves into the understanding of active and passive components, flicker noise analysis, and the impact of noise on the performance of a receiver. The lesson also explains how to analyze flicker noise, the role of transistors, and the impact of current flow on noise. It further discusses strategies to reduce noise, such as using a PMOS active load or a polysilicon resistor. The lesson concludes with an exploration of linearity in active mixers and how to improve it.

Video Highlights

00:25 - Flicker noise in active mixers
07:21 - How the amplitude of the square wave can reduce noise
11:40 - Explanation of how flicker noise is considered in the design of the mixer
25:36 - Active mixers 2nd order distortion
31:07 - Input FET 2nd order nonlinearity

Key Takeaways

- Flicker noise is a significant factor to consider in active mixers as it affects the entire receiver performance.
- The flicker noise in active mixers can be reduced by decreasing the current flowing through the switch or by using a PMOS active load.
- White noise at low frequencies is translated to DC during the frequency translation process in active mixers.
- The linearity of active mixers can be improved by reducing the parasitic capacitance at the common source of each switch.
- The noise and linearity of active mixers can be improved by reducing feed-through and parasitic capacitance.