Analog stages are designed by combining device transconductance, output resistance, and load impedances. Voltage gain often scales as $A_v \approx -g_m R_{out}$ for a transconductor driving a resistive load. Cascoding improves output resistance and bandwidth at the cost of headroom.

Frequency compensation is essential in multi-stage amplifiers because each pole reduces phase margin. Techniques such as Miller compensation, lead-lag networks, and feedforward paths are used to prevent oscillation while maintaining gain and speed. A robust design targets adequate gain margin and phase margin across process, voltage, and temperature corners.

Important noise sources include thermal noise, shot noise, flicker noise, and generation-recombination noise. In precision and low-frequency electronics, $1/f$ noise can dominate, while in RF and broadband systems thermal noise often sets sensitivity limits. Noise matching and bias optimization are therefore key design tasks.