SLVAEW7 September   2020 ADC12DJ5200RF , LMK00304 , LMK04828 , LMX2594 , TPS62912 , TPS62913

 

  1.   Trademarks
  2. 1Introduction and System Description
    1. 1.1 Introduction
      1. 1.1.1 ADC12DJ5200 Noise and Ripple Requirements
      2. 1.1.2 Power Supply Requirements for Wideband RF PLL and Clocks
      3. 1.1.3 TPS62913 Low-Noise and Low-Ripple Buck Converter
    2. 1.2 Block Diagram
    3. 1.3 Design Considerations
  3. 2Tests and Results
    1. 2.1 Test Methodology
    2. 2.2 Test Conditions
    3. 2.3 Test Results
  4. 3Conclusion
  5. 4References
  6. 5Appendix

2.3 Test Results

Performance tables and graphs comparing the original ADC12DJ5200RF Original EVM with the TPS62913 modified board are shown below.

Table 2-1 Signal to Noise (SNR) Comparison Table
Frequency (Hz)Original ADC12DJ5200RF EVM SNR (dBFS)TPS62913 ADC12DJ5200RF EVM SNR (dBFS)
349656677.254.34553.771
989659118.753.82953.659
239975128253.77553.643
449975433351.75451.846
589976959251.03650.864
799981231749.88949.525
GUID-20200917-CA0I-HTHB-THWM-HF35MQRKRCBL-low.gifFigure 2-6 Signal to Noise (SNR) Comparison Graph
Table 2-2 Spurious-Free Dynamic Range (SFDR) Comparison Table
Frequency (Hz) Original ADC12DJ5200RF EVM SFDR (dBFS) TPS62913 ADC12DJ5200RF EVM SFDR (dBFS)
349656677.2 61.327 63.344
989659118.7 61.015 62.243
2399751282 63.357 64.835
4499754333 56.525 59.718
5899769592 51.946 52.896
7999812317 50.945 52.623
GUID-20200917-CA0I-HCML-QM3R-HQHPSJJXMNXC-low.svgFigure 2-7 Spurious-Free Dynamic Range Comparison Graph
GUID-20200917-CA0I-PSJZ-N5SC-XQD4LD3TJ1SG-low.svgFigure 2-8 Noise Spectral Density Comparison Graph

The next plot, Figure 2-9, shows how no PSMR is observed with an analog input signal frequency of 1.2 GHz applied when using the original power design with SMPS and LDO, and the TPS62913 switching supply only.

GUID-20200914-CA0I-HKCK-DWNK-ZMHMW5KLMVDQ-low.gifFigure 2-9 PSMR Comparison of Original and TPS62913

Additionally, no visible modulation of the switcher power supply spur is seen around the carrier and at DC as seen in Figure 2-10.

GUID-20200914-CA0I-8GWV-GR31-NRB0ZK0DJSHW-low.svg Figure 2-10 PSMR Comparison of Original and TPS62913 at DC
Table 2-3 Power Loss Comparison
ConfigurationInput CurrentInput Power
Original Power Supply Configuration with SMPSs + LDOs828.2 mA9.938 W
TPS62913 Power Supplies only704.3 mA8.4516 W
Input Current and Power Savings123.9 mA1.4864 W

Below are thermal images of the power supplies running when taking data for the performance comparison tables.

GUID-20200916-CA0I-94MC-F6JX-CZ527BBM3J5R-low.gif
Note: Original Board DC/DC Max Temp is 36.2 C
Figure 2-11 Original Switching Converters
GUID-20200916-CA0I-WNTS-2GSF-RGS9N1NBMJBB-low.gif
Note: Original Board LDO Max Temp is 40.8 C
Figure 2-12 Original LDOs
GUID-20200916-CA0I-XJRH-145D-WBCWMWWGDWMM-low.gifFigure 2-13 TPS62913 Switching Converters
Note: TPS62913 Max Temp is 31.2 C