LNA Performance Simulations: Difference between revisions

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==Power Consumption==
==Power Consumption==
*Ground both the input and output of your LNA. If there is no DC blocking capacitor at the output then leave it open-circuited.
*Ground both the input and output of your LNA. If there is no DC blocking capacitor at the output then leave it open-circuited.
*Using the Analog Design Environment choose to run a dc simulation and make sure that ‘’’Save DC Operation Point’’’ is selected.
*Using the Analog Design Environment choose to run a dc simulation and make sure that '''Save DC Operation Point''' is selected.
*Run the simulation. When it is finished click ''’Results -> Print -> DC Operating Points''
*Run the simulation. When it is finished click '''Results -> Print -> DC Operating Points'''
*Click on the DC voltage source and note the delivered power.
*Click on the DC voltage source and note the delivered power.


==S-Parameter Simulations==
==S-Parameter Simulations==
*You must first instantiate ports at both the input and output of the LNA ''(analogLib -> Sources -> Independent -> port)''.
*You must first instantiate ports at both the input and output of the LNA '''(analogLib -> Sources -> Independent -> port)'''.
*Edit the properties of the input port  
*Edit the properties of the input port  
**Set the ''Resistance'' to 50 Ω and the ''Port number'' to 1.  
**Set the '''Resistance''' to 50 Ω and the '''Port number''' to 1.  
**Set the ''Source type'' to dc.
**Set the '''Source type''' to dc.
*Edit the properties of the output port
*Edit the properties of the output port
**Set the ''Resistance'' to 50 Ω and set the ''Port number'' to 2.
**Set the '''Resistance''' to 50 Ω and set the '''Port number''' to 2.
**Set the ''Source type'' to ''dc''.
**Set the '''Source type''' to '''dc'''.
*In the Analog Design Environment and choose the ''sp'' analysis type.
*In the Analog Design Environment and choose the '''sp''' analysis type.
**Click the ''Port Select'' button and select the input and output port on the schematic.
**Click the '''Port Select''' button and select the input and output port on the schematic.
**Set the ''Sweep Variable'' to ''Frequency''
**Set the '''Sweep Variable''' to '''Frequency'''
**Set the ''Sweep Range'' to ''Start-Stop'' and enter 1.5G for the ''Start'' value and 3.5G for the ''Stop'' value.
**Set the '''Sweep Range''' to '''Start-Stop''' and enter 1.5G for the '''Start''' value and 3.5G for the '''Stop''' value.
**Set the ''Sweep Type'' to Linear and the ''Number of Steps'' to 1000.
**Set the '''Sweep Type''' to Linear and the '''Number of Steps''' to 1000.
**Leave the ''Do Noise'' set to ''no''.
**Leave the '''Do Noise''' set to '''no'''.
**Click ''OK''
**Click '''OK'''
*Run the simulation
*Run the simulation
*To plot the results click ''Results -> Direct Plot -> Main Form ...''  
*To plot the results click '''Results -> Direct Plot -> Main Form ...'''  
**Make sure that the ''Analysis'' is ''sp'' and the ''Function'' is ''SP''
**Make sure that the '''Analysis''' is '''sp''' and the '''Function''' is '''SP'''
**Select ''Plot Type'' as ''Rectangular''
**Select '''Plot Type''' as '''Rectangular'''
**Set the ''Modifier'' to ''dB20''
**Set the '''Modifier''' to '''dB20'''
**Now simply click the button corresponding to the parameter you wish to plot.
**Now simply click the button corresponding to the parameter you wish to plot.


==Noise Figure using S-parameter Simulation==
==Noise Figure using S-parameter Simulation==
*Follow steps 1 – 4d from the S-parameter simulation instructions above.  
*Follow steps 1 – 4d from the S-parameter simulation instructions above.  
*In the ''sp'' Choosing Analyses window, set ''Do Noise'' to ''yes''
*In the '''sp''' Choosing Analyses window, set '''Do Noise''' to '''yes'''
**Select the Output Port
**Select the Output Port
**Select the Input Port
**Select the Input Port
**Click ''OK''
**Click '''OK'''
*Run the simulation
*Run the simulation
*To plot the results click ''Results -> Direct Plot -> Main Form ...''
*To plot the results click '''Results -> Direct Plot -> Main Form ...'''
**Make sure that the ''Analysis'' is ''sp'' and the Function is ''NF''
**Make sure that the '''Analysis''' is '''sp''' and the Function is '''NF'''
**Set the ''Modifier'' to ''dB10''
**Set the '''Modifier''' to '''dB10'''
**Click on ''Plot''
**Click on '''Plot'''


==IIP3  and 1-dB Compression Simulation==
==IIP3  and 1-dB Compression Simulation==
*You must first instantiate ports at both the input and output of the LNA (analogLib -> Sources -> Independent -> port)
*You must first instantiate ports at both the input and output of the LNA (analogLib -> Sources -> Independent -> port)
*Edit the properties of the input port
*Edit the properties of the input port
**Set the ''Resistance'' to 50 Ω
**Set the '''Resistance''' to 50 Ω
**Set the ''Port number'' to 1
**Set the '''Port number''' to 1
**''Source type'' should be ''sine''
**'''Source type''' should be '''sine'''
**Fill in ''fund1'' for the ''Frequency name 1''
**Fill in '''fund1''' for the '''Frequency name 1'''
**''Frequency 1'' should be 2.4G
**'''Frequency 1''' should be 2.4G
**This is the frequency of the desired signal
**This is the frequency of the desired signal
**Fill in ''prf'' for ''Amplitude 1'' (dBm)
**Fill in '''prf''' for '''Amplitude 1''' (dBm)
**This is a variable name (to be defined later) of the power of the input signal
**This is a variable name (to be defined later) of the power of the input signal
**Click on ''Display second sinusoid''
**Click on '''Display second sinusoid'''
**Fill in ''fund2'' for ''Frequency name 2''
**Fill in '''fund2''' for '''Frequency name 2'''
**''Frequency 2'' should be 2.42G
**'''Frequency 2''' should be 2.42G
**This is the frequency of the second tone or “blocker”
**This is the frequency of the second tone or “blocker”
**Fill in ''prf'' for ''Amplitude 2 (dBm)''
**Fill in '''prf''' for '''Amplitude 2 (dBm)'''
**This sets the power of the blocker equal to the power of the input signal
**This sets the power of the blocker equal to the power of the input signal
**Click ''OK''
**Click '''OK'''
*Edit the properties of the output port
*Edit the properties of the output port
**Set the ''Resistance'' to 50 Ω and the ''Port number'' to 2
**Set the '''Resistance''' to 50 Ω and the '''Port number''' to 2
**Set the ''Source type'' to ''dc''
**Set the '''Source type''' to '''dc'''
*In the Analog Design Environment we need to enable the pss analysis
*In the Analog Design Environment we need to enable the pss analysis
**Verify that fund1 and fund2 are displayed in the Fundamental Tones section.
**Verify that fund1 and fund2 are displayed in the Fundamental Tones section.
**Select Beat Frequency and click ''Auto Calculated''
**Select Beat Frequency and click '''Auto Calculated'''
***The beat frequency should be 20 MHz, this is the greatest common divisor of ''fund1'' and ''fund2''
***The beat frequency should be 20 MHz, this is the greatest common divisor of '''fund1''' and '''fund2'''
**Select Number of harmonics under ''Output harmonics'' and fill in the value of 123
**Select Number of harmonics under '''Output harmonics''' and fill in the value of 123
***This field defines the number of harmonics of the beat frequency that the simulation will consider. For IIP3 tests we need to consider up to the frequency (2*2.42GHz – 2.4GHz = 2.44GHz). This means that we need 122 harmonics of the beat frequency (2.44GHz / 20MHz = 122). We use 123 harmonics to go one harmonic higher.
***This field defines the number of harmonics of the beat frequency that the simulation will consider. For IIP3 tests we need to consider up to the frequency (2*2.42GHz – 2.4GHz = 2.44GHz). This means that we need 122 harmonics of the beat frequency (2.44GHz / 20MHz = 122). We use 123 harmonics to go one harmonic higher.
**Set the ''Accuracy Defaults (errpreset)'' to ''conservative''
**Set the '''Accuracy Defaults (errpreset)''' to '''conservative'''
**Set the'' Additional Time for Stabilization (tstab)'' to 20n
**Set the''' Additional Time for Stabilization (tstab)''' to 20n
***This allows any startup transients to settle before calculating the IIP3
***This allows any startup transients to settle before calculating the IIP3
**Click ''Sweep''
**Click '''Sweep'''
**Choose ''Variable'' and check'' no'' for Frequency Variable?
**Choose '''Variable''' and check''' no''' for Frequency Variable?
**Fill in prf for the variable name
**Fill in prf for the variable name
***This is the variable defining the power of both the input and blocker signals
***This is the variable defining the power of both the input and blocker signals
**Check'' Start-Stop'' under ''Sweep Range'' and fill in -50 for ''Start'' and 0 for'' Stop''
**Check''' Start-Stop''' under '''Sweep Range''' and fill in -50 for '''Start''' and 0 for''' Stop'''
**Set the Sweep Type to Linear and set the ''Step Size'' to 5
**Set the Sweep Type to Linear and set the '''Step Size''' to 5
**Click OK
**Click OK
*Run the simulation
*Run the simulation
*To view the results for IIP3 click'' Results -> Direct Plot -> Main Form ...''
*To view the results for IIP3 click''' Results -> Direct Plot -> Main Form ...'''
**Set the ''Analysis'' to'' pss''
**Set the '''Analysis''' to''' pss'''
**Set the ''Function'' to ''IPN Curves''
**Set the '''Function''' to '''IPN Curves'''
**Make sure that Select Port ( fixed R(port) ) is set
**Make sure that Select Port ( fixed R(port) ) is set
**Click Variable Sweep (“prf”) for Circuit Input Power
**Click Variable Sweep (“prf”) for Circuit Input Power
**Enter -25 for ''Input Power Extrapolation Point (dBm)''
**Enter -25 for '''Input Power Extrapolation Point (dBm)'''
***Some experimentation might be in order. You want the resulting extrapolated line to match well with the straight portion of the IM3 components at low power.
***Some experimentation might be in order. You want the resulting extrapolated line to match well with the straight portion of the IM3 components at low power.
**Select ''Input Referred IP3'' and ''Order 3rd''
**Select '''Input Referred IP3''' and '''Order 3rd'''
**Select either 2.44G (2*2.42G – 2.4G) or 2.38G (2*2.4G – 2.42G) for the 3rd Order Harmonic
**Select either 2.44G (2*2.42G – 2.4G) or 2.38G (2*2.4G – 2.42G) for the 3rd Order Harmonic
**Select 2.4G for the ''1st Order Harmonic''
**Select 2.4G for the '''1st Order Harmonic'''
**Select the output port on the schematic
**Select the output port on the schematic
**You Should get a plot similar to Fig. 1 below
**You Should get a plot similar to Fig. 1 below
***Note that I use AWD whereas the default waveform viewer in Cadence is Wavescan.
***Note that I use AWD whereas the default waveform viewer in Cadence is Wavescan.
*To View the results for the 1-dB compression point click ''Results -> Direct Plot -> Main Form ...''
*To View the results for the 1-dB compression point click '''Results -> Direct Plot -> Main Form ...'''
**Set the ''Analysis'' to ''pss''
**Set the '''Analysis''' to '''pss'''
**Set the ''Function'' to ''Compression Point''
**Set the '''Function''' to '''Compression Point'''
**Check that ''Select Port ( fixed R(port) )'' is set
**Check that '''Select Port ( fixed R(port) )''' is set
**Select'' Output Power'' for ''Format''
**Select''' Output Power''' for '''Format'''
**Enter 1 for ''Gain Compression (dB)''
**Enter 1 for '''Gain Compression (dB)'''
***We are interested in the 1-dB compression point after all
***We are interested in the 1-dB compression point after all
**Enter -25 for ''Input Power Extrapolation Point (dBm)''
**Enter -25 for '''Input Power Extrapolation Point (dBm)'''
***Again some experimentation might be in order
***Again some experimentation might be in order
**Select ''Input Referred 1 dB'' Compression
**Select '''Input Referred 1 dB''' Compression
**Under the ''1st Order'' Harmonics select 2.4G
**Under the '''1st Order''' Harmonics select 2.4G
**Select the output Port on the schematic
**Select the output Port on the schematic
**The resulting plot should look similar to Fig. 2 below.
**The resulting plot should look similar to Fig. 2 below.

Revision as of 17:11, 9 April 2010

Power Consumption

  • Ground both the input and output of your LNA. If there is no DC blocking capacitor at the output then leave it open-circuited.
  • Using the Analog Design Environment choose to run a dc simulation and make sure that Save DC Operation Point is selected.
  • Run the simulation. When it is finished click Results -> Print -> DC Operating Points
  • Click on the DC voltage source and note the delivered power.

S-Parameter Simulations

  • You must first instantiate ports at both the input and output of the LNA (analogLib -> Sources -> Independent -> port).
  • Edit the properties of the input port
    • Set the Resistance to 50 Ω and the Port number to 1.
    • Set the Source type to dc.
  • Edit the properties of the output port
    • Set the Resistance to 50 Ω and set the Port number to 2.
    • Set the Source type to dc.
  • In the Analog Design Environment and choose the sp analysis type.
    • Click the Port Select button and select the input and output port on the schematic.
    • Set the Sweep Variable to Frequency
    • Set the Sweep Range to Start-Stop and enter 1.5G for the Start value and 3.5G for the Stop value.
    • Set the Sweep Type to Linear and the Number of Steps to 1000.
    • Leave the Do Noise set to no.
    • Click OK
  • Run the simulation
  • To plot the results click Results -> Direct Plot -> Main Form ...
    • Make sure that the Analysis is sp and the Function is SP
    • Select Plot Type as Rectangular
    • Set the Modifier to dB20
    • Now simply click the button corresponding to the parameter you wish to plot.

Noise Figure using S-parameter Simulation

  • Follow steps 1 – 4d from the S-parameter simulation instructions above.
  • In the sp Choosing Analyses window, set Do Noise to yes
    • Select the Output Port
    • Select the Input Port
    • Click OK
  • Run the simulation
  • To plot the results click Results -> Direct Plot -> Main Form ...
    • Make sure that the Analysis is sp and the Function is NF
    • Set the Modifier to dB10
    • Click on Plot

IIP3 and 1-dB Compression Simulation

  • You must first instantiate ports at both the input and output of the LNA (analogLib -> Sources -> Independent -> port)
  • Edit the properties of the input port
    • Set the Resistance to 50 Ω
    • Set the Port number to 1
    • Source type should be sine
    • Fill in fund1 for the Frequency name 1
    • Frequency 1 should be 2.4G
    • This is the frequency of the desired signal
    • Fill in prf for Amplitude 1 (dBm)
    • This is a variable name (to be defined later) of the power of the input signal
    • Click on Display second sinusoid
    • Fill in fund2 for Frequency name 2
    • Frequency 2 should be 2.42G
    • This is the frequency of the second tone or “blocker”
    • Fill in prf for Amplitude 2 (dBm)
    • This sets the power of the blocker equal to the power of the input signal
    • Click OK
  • Edit the properties of the output port
    • Set the Resistance to 50 Ω and the Port number to 2
    • Set the Source type to dc
  • In the Analog Design Environment we need to enable the pss analysis
    • Verify that fund1 and fund2 are displayed in the Fundamental Tones section.
    • Select Beat Frequency and click Auto Calculated
      • The beat frequency should be 20 MHz, this is the greatest common divisor of fund1 and fund2
    • Select Number of harmonics under Output harmonics and fill in the value of 123
      • This field defines the number of harmonics of the beat frequency that the simulation will consider. For IIP3 tests we need to consider up to the frequency (2*2.42GHz – 2.4GHz = 2.44GHz). This means that we need 122 harmonics of the beat frequency (2.44GHz / 20MHz = 122). We use 123 harmonics to go one harmonic higher.
    • Set the Accuracy Defaults (errpreset) to conservative
    • Set the Additional Time for Stabilization (tstab) to 20n
      • This allows any startup transients to settle before calculating the IIP3
    • Click Sweep
    • Choose Variable and check no for Frequency Variable?
    • Fill in prf for the variable name
      • This is the variable defining the power of both the input and blocker signals
    • Check Start-Stop under Sweep Range and fill in -50 for Start and 0 for Stop
    • Set the Sweep Type to Linear and set the Step Size to 5
    • Click OK
  • Run the simulation
  • To view the results for IIP3 click Results -> Direct Plot -> Main Form ...
    • Set the Analysis to pss
    • Set the Function to IPN Curves
    • Make sure that Select Port ( fixed R(port) ) is set
    • Click Variable Sweep (“prf”) for Circuit Input Power
    • Enter -25 for Input Power Extrapolation Point (dBm)
      • Some experimentation might be in order. You want the resulting extrapolated line to match well with the straight portion of the IM3 components at low power.
    • Select Input Referred IP3 and Order 3rd
    • Select either 2.44G (2*2.42G – 2.4G) or 2.38G (2*2.4G – 2.42G) for the 3rd Order Harmonic
    • Select 2.4G for the 1st Order Harmonic
    • Select the output port on the schematic
    • You Should get a plot similar to Fig. 1 below
      • Note that I use AWD whereas the default waveform viewer in Cadence is Wavescan.
  • To View the results for the 1-dB compression point click Results -> Direct Plot -> Main Form ...
    • Set the Analysis to pss
    • Set the Function to Compression Point
    • Check that Select Port ( fixed R(port) ) is set
    • Select Output Power for Format
    • Enter 1 for Gain Compression (dB)
      • We are interested in the 1-dB compression point after all
    • Enter -25 for Input Power Extrapolation Point (dBm)
      • Again some experimentation might be in order
    • Select Input Referred 1 dB Compression
    • Under the 1st Order Harmonics select 2.4G
    • Select the output Port on the schematic
    • The resulting plot should look similar to Fig. 2 below.


[1]

Figure 1: Sample IIP3 plot

[2]

Figure 2: 1-dB Compression Point