TIDUDT4A May   2018  – November 2021 AM3351 , AM3352 , AM3354 , AM3356 , AM3357 , AM3358 , AM3358-EP , AM3359

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Power Rails Requirements of the System
      2. 2.2.2 Power Sequencing Requirements of the System
      3. 2.2.3 Uncontrolled Power Off
      4. 2.2.4 12-V Input Voltage Rail
    3. 2.3 Highlighted Products
      1. 2.3.1 TLV62568/9
      2. 2.3.2 LM3881
      3. 2.3.3 TLV803
      4. 2.3.4 AM335x
      5. 2.3.5 WL1837MOD
    4. 2.4 System Design Theory
      1. 2.4.1 Power Tree Architecture
      2. 2.4.2 Power Sequencing Solution
        1. 2.4.2.1 Design Steps for DC-DCs
        2. 2.4.2.2 Design Steps for the Sequencer
        3. 2.4.2.3 Design Steps for the Supervisor
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. 3.1.1.1 Connector Configuration of TIDA-01568
        2. 3.1.1.2 Procedure for Board Bring-up and Testing
      2. 3.1.2 Software
        1. 3.1.2.1 Description of Environment Implementation
        2. 3.1.2.2 How to Customize the Processor SDK for This Reference Design
      3. 3.1.3 Software Bring-up Tips
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
        1. 3.2.2.1 Power-Up and Power-Down Sequence Test
        2. 3.2.2.2 Typical Characteristics of DC-DCs
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 PCB Layout Guidelines
      2. 4.3.2 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7About the Author
  13. 8Revision History

3.2.2.2 Typical Characteristics of DC-DCs

Figure 3-8 shows the efficiency of the 5 voltage rails with 5-V DC supply.

GUID-FBA6831B-34B9-4B66-8135-9B532464DC4F-low.gifFigure 3-8 Efficiency of 5 Voltage Rails

To test the efficiency, four multimeters are used: two are set up as voltmeters to measure the input and output voltages, and two are set up as ammeters to measure the input and output currents. In addition, an electronic load is used to achieve different currents.

Table 3-4, Table 3-5, Table 3-6, Table 3-7, and Table 3-8 list the details of the efficiency curves shown in Figure 3-8.

Table 3-4 Efficiency of 1.8-V Rail
VIN(V)IIN(mA)VOUT(V)IOUT(V)η(%)
4.9724.551.80710.4983.79
4.9498.521.80619.6784.25
4.92412.971.80429.9784.66
4.89917.281.80239.9184.95
4.87621.381.80249.2385.10
4.8525.951.80259.5285.22
4.82330.661.80270.385.67
4.79834.911.80180.1386.16
4.77339.311.79690.3686.49
4.74943.531.796100.287.05
4.49188.581.789199.5589.74
4.911121.11.785298.6589.64
4.883160.11.7839690.16
4.85206.681.775505.389.48
4.822245.641.77594.2388.80
4.786295.551.765703.7587.81
4.754339.951.76797.2586.82
4.718388.681.756896.1785.82
4.718440.61.75100384.44
Table 3-5 Efficiency of 1.1-V Rail
VIN(V)IIN(mA)VOUT(V)IOUT(V)η(%)
5.022.741.088310.0879.75
55.521.0920.480.57
4.9888.221.0930.3780.74
4.97410.731.08939.8281.25
4.95813.531.08750.3981.65
4.94216.231.08660.5481.97
4.92718.951.08570.7482.21
4.91321.361.08479.7882.41
4.89624.241.08390.6482.71
4.88126.991.082100.8882.86
4.71555.971.073206.9384.14
4.57480.631.0688299.5486.81
4.395111.81.064399.986.59
4.944126.741.0595500.1784.57
4.924154.41.055600.983.39
4.904182.631.05699.1581.97
4.881213.61.04680280.46
4.858245.661.04903.4778.73
4.834278.51.036100277.11
Table 3-6 Efficiency of 3.3-V Rail
VIN(V) IIN(mA) VOUT(V) IOUT(V) η(%)
4.968 7.6 3.319 10.45 91.86
4.93 14.18 3.318 19.46 92.36
4.885 21.9 3.317 29.94 92.83
4.846 28.69 3.314 38.95 92.84
4.8 36.67 3.313 49.42 93.02
4.753 44.79 3.31 59.91 93.15
4.712 51.88 3.31 68.92 93.32
4.663 60.28 3.31 79.4 93.50
4.613 68.85 3.31 89.88 93.67
4.57 76.37 3.31 98.9 93.80
4.898 143.46 3.296 199.21 93.44
4.84 216.12 3.2866 299.6 94.13
4.78 289.16 3.2823 398.51 94.63
4.715 367.1 3.2778 498.89 94.48
4.643 448.84 3.2736 599.17 94.12
4.565 534.06 3.2695 698.05 93.61
4.472 626.51 3.2655 798.38 93.05
4.276 746 3.262 898.72 91.90
4.18 853.2 3.2585 1000 91.37
Table 3-7 Efficiency of 1.35-V Rail
VIN(V)IIN(mA)VOUT(V)IOUT(V)η(%)
4.9923.571.35310.781.23
4.9746.661.35619.8581.25
4.955101.354530.182.28
4.93513.511.353140.6482.48
4.91716.591.35249.9782.82
4.898201.351260.383.17
4.87923.211.35169.883.27
4.85926.71.3580.3483.60
4.83930.311.34891.3683.97
4.82332.971.34799.4684.25
4.6366.541.3420086.99
4.432101.271.3344298.4488.73
4.923122.961.3296397.6687.35
4.9155.161.325498.0886.80
4.873191.271.3196605.885.77
4.848225.041.315702.284.64
4.823260.341.31798.9483.35
4.7933001.305905.3282.16
4.764340.21.3100380.45
Table 3-8 Efficiency of 1.325-V Rail
VIN(V)IIN(mA)VOUT(V)IOUT(V)η(%)
4.9933.421.32210.4680.98
4.9766.381.32519.4581.18
4.9569.731.32329.9482.14
4.9412.631.32238.9482.51
4.921161.3249.4282.85
4.919.41.3259.9183.19
4.8822.811.318770.483.40
4.86525.721.31879.483.63
4.84629.11.316589.8783.90
4.82632.441.3146100.484.31
4.6464.651.3075199.286.82
4.4499.141.3027299.5988.66
4.924120.481.298398.587.19
4.91521.2933498.986.63
4.877184.851.2886599.285.65
4.852218.661.28469884.48
4.825254.51.279798.3783.16
4.798291.961.274898.781.73
4.769330.61.2696100080.53

Figure 3-9 shows the output voltage ripple of the 1.8-V rails at 4 different loads.

GUID-1D21343E-AFED-4401-9FDC-FA2FE3B24304-low.gifFigure 3-9 Output Voltage Ripple of 1.8 V at 4 Different Output Load

The output voltage ripple remains below 30 mVpp under a full load (1 A), light load (10 mA), 100mA and no load. This test result has a large margin, comparing the 5% requirement. The device automatically enters PSM to improve efficiency at light load when the inductor current becomes discontinuous. In PSM, the converter reduces switching frequency and minimizes current consumption.

The other power supply rails' ripple are similar to the 1.8-V rail, refer to the TLV62568/9's data sheet for more details.