Basic MOS Amplifiers: DC and Low-Frequency Behavior

Amplifiers are among the most important and most widely used sub-blocks of analog integrated circuits. In this chapter, the DC and low-frequency behaviors of the resistor-loaded basic amplifier circuits are reviewed, including the common source, common base, and source-follower amplifiers. Then, more complicated and important components of the analog ICs are investigated in detail: the active loaded amplifiers, the long-tailed pairs (differential amplifiers), and the OTAs (operational transconductance amplifiers), including their large signal behaviors. The common-mode feedback concept is also investigated in this chapter, which is important for various differential structures to reduce the common-mode gain.