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## How to define for "Freq" and "Noise" of vdc source in analogLib , cadence

when i do phasenoise simulation in VCO, i find that filling some value in "freq" and "noise" for example 1 and 1, the result of phasenoise entirely changed. So i doubt what value in those box is reasonable. the doc of cadence gives almost no comment. anyone could please tell me if you know, thanks

## op-amp noise simulation

Hi guys, I have designed a 2 stage op-amp, diff input and single output. I use cadence spectre simulation tool. All the specs are pretty good. Now I want to calculate the open loop input referred noise of OTA. But I have a question in noise simulation and I dont know if the results I get are correct or not!!! I want to perform (...)

I want to use VPWLF source to add random noise-like signal as input of my circuit. The file format for the signal is TXT(with time and voltage columns), can it be directly put into the "PWL file name" property of the source? I cannot run simulation in spectre and the error is: ERROR(CMI-2011):Unable to open waveform file: "randomn"(this is the

## Plot NF vs QL in Cadence

Does anyone know how to plot NF vs QL in cadence where QL=1/(Rs*Cgg*Ωο)? I did the following simulation steps: 1) I defined QL in calculator window 2) I ran a noise Analysis simulation at 5Ghz (Sweep Variable=Vgg 0->1.2) 3) I Plotted both NF vs Vgg and QL vs Vgg at the same graph windows and then plot NF vs QL using Axis attr

## Plot NFmin vs IDS bias condition

Hi. Does anyone know how to plot NFmin vs IDS bias in cadence? Or does anyone know the exactly mathematical formula of NFmin? My circuit is a MOS LNA with inductive source degeneration. Thanks If you have a valid nonlinear model, you can obtain NFmin vs. IDS by doing noise analysis.Because nonlinear

## Measuring Res of subtrheshold cascaded pmos

While you can get very large resistances with subthreshold FETs, any noise will give you large temporal variations in the effective resistance. It is by no means a reliable resistance.

## Which Noise analysis for RF design?

I have to simulate the noise performances (with Spectre) of an active bandpass filter working up to 1.5 GHz. It's 50ohm input/output matched and what I do not understand is which noise analysis I must use. First, I used noise analysis in cadence and during the design I noticed clear noise improvement by (...)

Hi all, after reading all there is to read in this site on transient noise simulation. i steel dont understand how to calibrated the simulation. can someone please write me a step-by-step on how to do it. (a simple example would be great) thanks alot.. Zvika.

## How to calculate signal-to-distortion ratio in Cadence

This is a system problem, not circuit.Therfore, you should model your system with the same conditions and then you may check your signal quality.You can not predict how much PN will be contributed from interferer channel and channel noise. Use system simulation..

## how to calculate THD and input reffered noise in cadence

I have design a active Gm-RC analog baseband filter in 0.18u CMOS process. I want to calculate THD and input reffered noise for filter. How can i calculate?

## how to use cadence to simulate PLL

noise Aware PLL Flow is also covered in Spectre RF documentation (User Guide, Theory vol1 and 2)

## how to model a substrate with cadence?

Hi, I shall model a substrate to analyze the substrate noise. There are several methods existed: solving numerical analysis, or using a CAD tool that can provide a RC network of substrate from a design layout. Because the substrate is lacking, some parameters of the substrate’s as well as the design layout can not be simulated or measured.

## Help me improve VCO performance

Hi Guys, I am simulating a VCO with the following design: Process: 0.18 um Tool: cadence Spectre Topology:Three stage Differential amplifier (with symmetric load) Supply: 3.3V Frequency: 2.4GHz I measured the phase noise and it was -100 dbc/Hz at 10 MHz. Is this a good performance? I am using a DC control voltage of about 875 mV. How

## Cadence :Gain, Stability, Noise for Analog Circuit

Dear All, I have designed the following two-stage-op-amp (CMOS .18um technology) in cadence. I am new in analog IC design. What are the steps to plot graphs for Gain, Stability and noise for this circuit. Gain Bandwidth is 5M Hz and VDD= 2.5 V. Thanks.

## help with proper noise source in Cadence

Hello All I am simulating a mixer in cadence and for measuring its NF I am using PSS+Pnoise. in Pnoise setting, for setting input and output we have options of voltage source and probe for output. The former option takes into account the noise added by port's internal resistor itself while the latter does not. The (...)

## opamp load capacitance for active filter design

Why do you want to chose your capacitors in the filter based on stability? According to me those should be based on noise. I would chose caps and resistors based on noise, then design the opamps accordingly.

## When did Cadence start to support transient noise analysis?

Anybody knows when did cadence start to support transient noise analysis?

## Noise separation in phase noise simulation

Hi Im doing a phase noise simulation in cadence (using MMSIM70) Im using the option "noise separation" to determine the amount of noise introduced by each instance in my circuit. However, when i compare the total output noise (in the band of interest) with the sum of the individual contribution of each (...)

## Is the resistor model in analogLib of Cadence noise-free?

I believe cadence can do transient noise analysis. Right. In the ADE (Analog Design Environment) menu, select Analyses -> Choose... In the Choosing Analyses menu, if you select the (default) tran analysis, you may also select Transient noise, which extends the menu for special n

## Cadence spectre phase noise plots for oscillators

Close in PN is in fact "Shot noise Contribution" and Shot noise can not be modelled well due to its natural cause is not well defined.But simulators should do an extrapolation and that's why close-in PN may be greater than zero.