Design-and-Layout-Implementation-of-Two-stage-Opamp-using 180nm-Technology

Design and Layout implementation of a high-performance two-stage Operational Amplifier (OPAMP) using 180nm semiconductor technology. Achieved required gain, bandwidth, and power efficiency through simulation and characterization.

2 Stage OPAMP Description

1. Two-Stage Amplification:

   • The op-amp consists of two amplification stages: a first stage called the input differential amplifier, and a second stage called the output amplifier.
   • The input stage amplifies the difference between two input voltages, while the output stage further amplifies this signal to produce a high-gain output.

2. Miller Capacitance:

   • Miller compensation is a technique that involves adding a capacitor across the input and output of the amplifier to effectively increase its bandwidth without sacrificing stability.
   • In a Miller-compensated two-stage op-amp, a capacitor is placed between the input and output nodes of the amplifier. This creates a feedback loop that modifies the amplifier's frequency response.

3. Increased Bandwidth:

   • By introducing the Miller capacitance, the pole frequency of the op-amp is shifted, effectively increasing its bandwidth. This means that the op-amp can respond to higher-frequency signals.

4. Stability Improvement:

   • Miller compensation helps to stabilize the op-amp by reducing the possibility of oscillation, especially at high frequencies. This is crucial for applications where a stable output is essential.

5. Trade-offs:

   • While Miller compensation enhances bandwidth and stability, it may introduce additional phase shift in the frequency response, which can affect the amplifier's performance in certain applications.

6. Applications:

   • Miller-compensated two-stage op-amps are commonly used in high-frequency applications where both bandwidth and stability are critical factors, such as in communication systems, instrumentation amplifiers, and other precision electronics.

Circuit

Design-Specification

Check out each process technology folder

Design Process

(W/L) ratio of M3,M4 is found using ICMR(+)
(W/L) ratio of M1,M2 is found using GBW
I5 is found using Slew Rate
(W/L) ratio of M5 is found using ICMR(-)
(W/L) ratio of M6 is found from Gain and design of M3, M4

Technology Used

180nm

References

CMOS Analog Circuit Design - Book by Douglas Holberg and Phillip E. Allen
Youtube

Status

Ongoing