Enerio - TwoStage Hands-On

7/29/2019 Enerio - TwoStage Hands-On

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ANALOG INTEGRATED CIRCUITS

Two-Stage Amplifier

Hands-on

Submitted by:

Rey PJ A. Enerio

BSECE 4

Submitted to:

Prof. Olga Joy L. Gerasta

October 2, 2012


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Two-Stage Amplifier Model

Basic Structure

The MOSFET model is an example of a Two-Stage Amplifier. The first-stage is constructed by Mp1, Mp2, Mn3, Mn4

and a constant current source Mp5as a differential amplifier. The second-stage is constructed by Mp7 and Mn6 as a

Common Source Amplifier. The 2 NMOS at the lower left of the design is our current source.

Operational Amplifier Specification


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Step 1. Using the Operational Amplifier Specification stated above, do Design Procedure through Hand

calculations. One must determine each devices size, every FETs W/L ratio and and the current that flows

in it.

Step. 2. Design an amplifier, measuring all the important OP parameters and implement your design

using Synopsys tool.

Two-Stage Amplifier Design Symbol

The op amp uses a dual-polarity power supply (Vdd and Vss) so the ac signals can swing above and below ground

and also be centered at ground.

Vin -

Vin +

Vout


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Two-Stage Amplifier Design using Synopsys

Gain, Phase Margin, Gain Bandwidth

A two-stage amplifier must have an Open-Loop gain from 60 100 dB. To ensure that our model is stable, it must

have a phase margin from 45 degrees to 90 degrees or better yet, ensure that you reach a phase margin close to 60

degrees. Also, try to have gain bandwidth greater than 5MHz.


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Common Mode Rejection Ratio

With a two-stage amplifier, you must attain a Common Mode Rejection Ratio equal to 60-80 dB.

CMRR = Ad - Acm

Input Common Mode Range

For input common mode range, you must attain a voltage value equal to 0.7V to 3V.


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Output Voltage Swing

Power Supply Rejection Ratio

With the time allotted considering the availability of the computer access, I was able to design circuits measuring

all the important OP parameters and implemented it design using Synopsys tool. However, I was not able

to complete the analysis to give way for others to start using the Synopsys tool.


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HSpice Coding


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Describe the function of each MOSFET components.

Mp5 is a constant current source which supplie

current to the remaining part of the design.

Mp5 and Mp8 are current mirrors, at the same

time mirrored with Mp7.

(W/L)p5 = (W/L)p8 = 12

Mp1 and Mp2 is our differential side for our

inputs Vin+ and Vin-.

Since current IBD is divided into 2, thus

(W/L)p1 = (W/L)p2 = 6

Mn3 and Mn4 is a current mirror.

Since Mn3 and Mn4 is NMOS in nature, thus it

has higher mobility than PMOS. Its dimension

will be divided by 2 to 3 times to compensate

the current crossing it.

W L n3 = W L n4 = 2

IBB is our current source which in my design isequal to 2 diode connected NMOS.

Mp7 is our circuit booster, part of the second

stage of our design which is responsible in

amplifying the signal.

(W/L)p7 = 50

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Enerio - TwoStage Hands-On