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| *[[LNA Performance Simulations]] - How to simulate a low-noise amplifier using SpectreRF | | *[[LNA Performance Simulations]] - How to simulate a low-noise amplifier using SpectreRF |
| *[[Integrated Inductor Design using ADS Momentum]] - Integrated inductor design procedure using Cadence and ADS Momentum | | *[[Integrated Inductor Design using ADS Momentum]] - Integrated inductor design procedure using Cadence and ADS Momentum |
| LOW NOISE AMPLIFIER PERFORMANCE SIMULATIONS
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| 1. Power Consumption
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| 1. Ground both the input and output of your LNA. If there is no DC blocking capacitor at the output then leave it open-circuited.
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| 2. Using the Analog Design Environment choose to run a dc simulation and make sure that Save DC Operation Point is selected.
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| 3. Run the simulation. When it is finished click Results -> Print -> DC Operating Points
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| 4. Click on the DC voltage source and note the delivered power.
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| 2. S-Parameter Simulations
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| 1. You must first instantiate ports at both the input and output of the LNA (analogLib -> Sources -> Independent -> port).
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| 2. Edit the properties of the input port
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| a. Set the Resistance to 50 Ω and the Port number to 1.
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| b. Set the Source type to dc.
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| 3. Edit the properties of the output port
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| a. Set the Resistance to 50 Ω and set the Port number to 2.
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| b. Set the Source type to dc.
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| 4. In the Analog Design Environment and choose the sp analysis type.
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| a. Click the Port Select button and select the input and output port on the schematic.
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| b. Set the Sweep Variable to Frequency
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| c. Set the Sweep Range to Start-Stop and enter 1.5G for the Start value and 3.5G for the Stop value.
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| d. Set the Sweep Type to Linear and the Number of Steps to 1000.
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| e. Leave the Do Noise set to no.
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| f. Click OK
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| 5. Run the simulation
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| 6. To plot the results click Results -> Direct Plot -> Main Form ...
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| a. Make sure that the Analysis is sp and the Function is SP
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| b. Select Plot Type as Rectangular
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| c. Set the Modifier to dB20
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| d. Now simply click the button corresponding to the parameter you wish to plot.
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| 3. Noise Figure using S-parameter Simulation
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| 1. Follow steps 1 – 4d from the S-parameter simulation instructions above.
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| 2. In the sp Choosing Analyses window, set Do Noise to yes
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| a. Select the Output Port
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| b. Select the Input Port
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| c. Click OK
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| 3. Run the simulation
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| 4. To plot the results click Results -> Direct Plot -> Main Form ...
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| a. Make sure that the Analysis is sp and the Function is NF
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| b. Set the Modifier to dB10
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| c. Click on Plot
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| 4. IIP3 and 1-dB Compression Simulation
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| 1. You must first instantiate ports at both the input and output of the LNA (analogLib -> Sources -> Independent -> port)
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| 2. Edit the properties of the input port
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| a. Set the Resistance to 50 Ω
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| b. Set the Port number to 1
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| c. Source type should be sine
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| d. Fill in fund1 for the Frequency name 1
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| e. Frequency 1 should be 2.4G
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| i. This is the frequency of the desired signal
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| f. Fill in prf for Amplitude 1 (dBm)
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| i. This is a variable name (to be defined later) of the power of the input signal
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| g. Click on Display second sinusoid
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| h. Fill in fund2 for Frequency name 2
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| i. Frequency 2 should be 2.42G
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| i. This is the frequency of the second tone or “blocker”
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| j. Fill in prf for Amplitude 2 (dBm)
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| i. This sets the power of the blocker equal to the power of the input signal
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| k. Click OK
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| 3. Edit the properties of the output port
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| a. Set the Resistance to 50 Ω and the Port number to 2
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| b. Set the Source type to dc
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| 4. In the Analog Design Environment we need to enable the pss analysis
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| a. Verify that fund1 and fund2 are displayed in the Fundamental Tones section.
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| b. Select Beat Frequency and click Auto Calculated
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| i. The beat frequency should be 20 MHz, this is the greatest common divisor of fund1 and fund2
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| c. Select Number of harmonics under Output harmonics and fill in the value of 123
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| i. 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.
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| d. Set the Accuracy Defaults (errpreset) to conservative
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| e. Set the Additional Time for Stabilization (tstab) to 20n
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| i. This allows any startup transients to settle before calculating the IIP3
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| f. Click Sweep
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| g. Choose Variable and check no for Frequency Variable?
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| h. Fill in prf for the variable name
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| i. This is the variable defining the power of both the input and blocker signals
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| i. Check Start-Stop under Sweep Range and fill in -50 for Start and 0 for Stop
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| j. Set the Sweep Type to Linear and set the Step Size to 5
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| k. Click OK
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| 5. Run the simulation
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| 6. To view the results for IIP3 click Results -> Direct Plot -> Main Form ...
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| a. Set the Analysis to pss
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| b. Set the Function to IPN Curves
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| c. Make sure that Select Port ( fixed R(port) ) is set
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| d. Click Variable Sweep (“prf”) for Circuit Input Power
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| e. Enter -25 for Input Power Extrapolation Point (dBm)
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| i. 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.
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| f. Select Input Referred IP3 and Order 3rd
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| g. Select either 2.44G (2*2.42G – 2.4G) or 2.38G (2*2.4G – 2.42G) for the 3rd Order Harmonic
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| h. Select 2.4G for the 1st Order Harmonic
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| i. Select the output port on the schematic
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| j. You Should get a plot similar to Fig. 1 below
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| i. Note that I use AWD whereas the default waveform viewer in Cadence is Wavescan.
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| 7. To View the results for the 1-dB compression point click Results -> Direct Plot -> Main Form ...
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| a. Set the Analysis to pss
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| b. Set the Function to Compression Point
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| c. Check that Select Port ( fixed R(port) ) is set
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| d. Select Output Power for Format
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| e. Enter 1 for Gain Compression (dB)
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| i. We are interested in the 1-dB compression point after all
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| f. Enter -25 for Input Power Extrapolation Point (dBm)
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| i. Again some experimentation might be in order
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| g. Select Input Referred 1 dB Compression
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| h. Under the 1st Order Harmonics select 2.4G
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| i. Select the output Port on the schematic
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| j. The resulting plot should look similar to Fig. 2 below.
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| Figure 1: Sample IIP3 plot
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| Figure 2: 1-dB Compression Point
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| ==Digital Tutorials== | | ==Digital Tutorials== |