/Miller-Compensated-Two-stage-OPAMP-using-SKY130PDK

Design of miller compensated 2 stage opamp using open source SKY130PDK

MIT LicenseMIT

Miller Compensated two stage OPAMP using SKY130 PDK

Design of miller compensated 2 stage opamp using open source SKY130PDK

Specification

  • DC Gain: 60dB
  • GBW(Gain Bandwidth): 5MHz
  • PDK: SKY130PDK
  • Phase Margin(PM): >=60°
  • Slew Rate: 10V/sec
  • ICMR(+): 1.2V
  • ICMR(-): 0.8V
  • CL(Load Capacitance): 10pF
  • Power Dissipation: <=80uW(this is bcs of the large load capacitance)
  • VDD=1.8V

Circuit Diagram

The circuit of an OPAMP includes a Differential Stage which contains a differential pair and current mirror. It also includes an Amplification stage to increase the gain.

Image

Design and Analysis

  • You can check out the Design and Analysis of the OPAMP here.
  • Design Overview
    • (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

Schematic

2stageopamptrynew Twostageopamp_try2

Gain and Phase Margin

  • Achieved specifications:
    • DC gain: 60 dB, GBW(new): 10 MHz, Phase Margin(new): 80°, Power Dissipation : 41μW (because of the large CL), Slew Rate: 9.06V/sec, CMRR: 71dB

Phase

OPAMP_BodePlot

Implementation

Implementation

Layout

  • I have to start.

References