运放基本仿真步骤

a
12
Test-Bench of CMRR
Where, V N V P V c m V C O M _ IN V A C
VCOM_IN is the input common voltage, VAC is a AC voltage for AC Sweep.
DC Sweep VP -VN (large signal) AC Sweep VP -VN with fixed frequency
(small signal)
a
5
Test-Bench of Open-Loop Differential Gain (method 1)
DC Sweep VP -VN (large signal)
Waveform of Open-Loop Differential Gain (method 2)
AV20log10VO U T
The results of the two methods are different, In fact, method 1 is more accurate for DC gain.
To create a symbol of a schematic: From Design->Create Cellview->From Cellview
a
4
Open-Loop Differential Gain
Two methods of simulating Open-Loop Differential Gain is available in ADE (Analog Design Environment)
a
9
ADE of Open-Loop Differential Gain (method 2)
To add a model for the simulation From ADE->Setup->Model libraries
Fixed Freq
To create a AC Sweep a From ADE->Analyses->Choose->A1C0
a
VOUT -VCOM_OUT
Differential Gain is 71.56dB
8
Test-Bench of Open-Loop Differential Gain (method 2)
AC Sweep VP -VN with fixed frequency
Setup VN
Setup VP
In this method, VP=VCM_IN+ x +VAC, and VN=VCM_IN Where, VCM_IN is the input common voltage, x is a design variables, VAC is a AC voltage for AC Sweep.
Setup VN
Setup VP
In this method, VP=VCM_IN +x, and VN=VCM_IN-x Where, VCM_IN is the common voltage, x is a design variables.
a
6
ADE of Open-Loop Differential Gain (method 1)
a
2
The Schematic of Folded Cascode Op-Amp
VDD
IBIAS=30nA
VDD=5V
10/5 M=1
VBIAS=1.2V
12/12 M=1
GND
BIAS
Folded Cascode
24/12 M=1
48/12 M=6
6/12 M=1
VP
48/12 48/12
VN
M=2
Differential Gain is 65.56dB
a
11
Common-mode Rejection Ratio
Vcm VP
VN Vcm
VOUT
VO U T AC
AC 1
Vcm 1A VAC A V CM RR
AC
AV CMRR
You can get detail illustration from “CMOS Analog Circuit Design”, Phillip E. Allen, Oxford University Press, Inc.
折叠式级联运放的仿真
a
1
The Typical Performance of Op-Amp
Open-Loop Differential Gain (AV) Common-mode Rejection Ratio (CMRR) Power Signal Rejection Ratio (PSRR) Phase Margin (PM) Input Common Mode Range (ICMR) Output Swing Range (OSR) Input/Output Impedance (CIN/ROUT) Slew Rate Noise
M=2
10/5
10/5
M=1
M=1
12/12 M=1
48/12 M=4
6/12 M=1
VOUT
VP
VN
VOUT
10/5 M=1
In order to decease the power
Consumption, IBIAS is only 30nA.
48/12 M=4
a
Байду номын сангаас
3
Create Schematic and Symbol in Spectre
To add a model for the simulation From ADE->Setup->Model libraries
To create a DC Sweep a From ADE->Analyses->Choose->DC7
Waveform of Open-Loop Differential Gain (method 1)
To obtain VCOM_OUT From Calculator-> Special Functions->Value
A VV O U T V P V C V O M N _O U TV O U T V 2C xO M _O U T
Where, VCOM_OUTVOUT|x0
To obtain DC gain From Calculator-> Special Functions->deriv