SNAA360 June   2022 ADC32RF54 , ADC32RF55 , AFE7950 , LMX1204

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
    1. 1.1 Cascaded LMX1204 Design
  4. 2Results
    1. 2.1 Single Device Performance
    2. 2.2 Cascaded Device Performance
    3. 2.3 Detailed Results
      1. 2.3.1 1 GHz Performance
      2. 2.3.2 3 GHz Performance
      3. 2.3.3 6 GHz Performance
      4. 2.3.4 10 GHz Performance
      5. 2.3.5 12.8 GHz Performance
    4. 2.4 Cascaded LMX1204 Performance With ADC32RF54
    5. 2.5 Cascaded LMX1204 Performance With AFE7950
  5. 3Summary
  6. 4References

2.3.3 6 GHz Performance

Figure 2-5 shows phase noise at offset frequencies is quite similar for all sources out to an offset frequency of 800 kHz, which is similar to the 3 GHz carrier frequency measurements. Again, a noise floor discrepancy appears between the LMX1204EVM measurement and the cascaded LMX1204 design measurement. This elevated noise floor is caused by the additive thermal noise of the second LMX1204 stage.

Figure 2-5 Phase Noise Comparison - 6 GHz

The difference between the two LMX1204 device noise floors is 2.2 dB on average. Use this to estimate the noise floor of a system with N stages of cascaded LMX1204 devices near 6 GHz.