Help me on 1/f noise calculation!

[guamak_menanak]

Below are the equation for MOSFET of 1/f

Vn(1/f noise) = rt[(Kf*gm*gm)*r0*r0/(f*Cox*W*L)]

where Kf = Flicker noise coefficient
f = frequency
r0 = output resistance of the circuit

Problem

1. What is the value of the ferquency? f3db@GBW@frequency that we pick?

Example

kf = 2f
gm = 2.83m
Cox = 1.132m
(W/L) = 102u/1.2u
r0 = 1955
f = 2.66 GHz (Pick any values,example 2.66GHz)

Vn(1/f noise) = rt[(2f*2.83m*2.83m)*1955*1955/(2.66G*1.132m*102u*1.2u)]

= 14.52 uV/rt(Hz)

But...in simulation, it gives 9.8 uV/rt(Hz)!

Is my calculation is true?
Hope someone could help!

 

[flatulent]

One clue is that the two answers are related by the factor square root of 2. This points to peak vs. RMS or other such things.

 

[guamak_menanak]

Did you mean Calculation = Simulation*rt[2] ?

I've tried to calculate them but still don't get the exatc value!

Simulation = 9.8 uV/rt[Hz]
Calculation = 14.52 uV/rt[Hz]

New Equation = 9.8u*rt[2]
= 13.85 uV/rt[Hz]
* Differ about 0.67u, is this value is acceptable?

Sorry to ask a silly question...
I'm 'blur' on noise analysis... 8O

 

[guamak_menanak]

Below are my netlist file and the waveform!

* Main circuit: simple amp-resistor
M1 out in Gnd Gnd NMOS L=1.2u W=102u AD=66p PD=24u AS=66p PS=24u
R2 Vdd out 2k TC=0.0, 0.0
v3 N2 Gnd 0.0 AC 1.0 0.0
v4 in N2 1
* End of main circuit: simple amp-resistor

vvdd Vdd 0 3

*N97N SPICE LEVEL1 PARAMETERS* TECHNOLOGY: SCN12 FEATURE SIZE: 1.2 microns
*COMMENTS: American Microsystems, Inc. 1.2 micron ABN.
* DATE: Sep 13/99
* LOT: n97n WAF: 04
.MODEL NMOS NMOS LEVEL=3 PHI=0.700000 TOX=3.0500E-08 XJ=0.200000U TPG=1
+ VTO=0.6063 DELTA=4.7620E-01 LD=1.2100E-07 KP=7.6456E-05
+ UO=675.3 RSH=6.8720E+01 GAMMA=0.6693
+ NSUB=1.7300E+16 NFS=5.9080E+11 VMAX=2.0890E+05
+ KAPPA=3.8640E-01 CGDO=2.0549E-10 CGSO=2.0549E-10
+ CGBO=4.4943E-10 CJ=2.8197E-04 MJ=5.3962E-01 CJSW=1.3603E-10
+ MJSW=1.0000E-01 PB=9.9000E-01 KF=2.0E-15
* Weff = Wdrawn - Delta_W
* The suggested Delta_W is 1.4000E-06

.ac DEC 5 1k 1000G
.noise v(out,in) v3
.temp 17
.print noise dn(M1,FN) *print 1/f noise for M1*

I've tried to use the factor of rt[2] but it can't be used for lower freq!

Example

Simulation = 74 uV/rt[Hz]
Calculation = 74.9 uV/rt[Hz]

New Equation = Simulation*rt[2]
= 74u*rt[2]
= 105.9 uV/rt[Hz] - differ with previous calculation=74.9 uV/rt[Hz]

Help me....