TIDUFB3 July   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TPS7H5006-SEP
      2. 2.3.2 TPS7H6025-SEP
      3. 2.3.3 TPS7H1111-SEP
      4. 2.3.4 TPS7H4010-SEP
      5. 2.3.5 TPS73801-SEP
      6. 2.3.6 TPS7H3302-SEP
      7. 2.3.7 TPS7H3014-SEP
      8. 2.3.8 TPS7H2221-SEP
      9. 2.3.9 SN54SC6T14-SEP
  9. 3System Design Theory
    1. 3.1 0V8 Discrete Buck Regulator (VCCINT)
      1. 3.1.1 VCCINT Load Step
    2. 3.2 Buck Regulators (Integrated)
      1. 3.2.1 1V2
      2. 3.2.2 1V2_VCCO
      3. 3.2.3 1V2_MEM
      4. 3.2.4 2V5_DDR_VPP
      5. 3.2.5 3V3_VCCO
    3. 3.3 Linear Regulators
      1. 3.3.1 DDR Termination
      2. 3.3.2 0V92
      3. 3.3.3 1V5_GTY
      4. 3.3.4 1V5
      5. 3.3.5 5V0_SYS
    4. 3.4 Sequencing
      1. 3.4.1 TPS7H3014-SP Sequencer
      2. 3.4.2 TPS7H2221-SEP Discharge Circuit
      3. 3.4.3 VCCINT Discharge Circuit
  10. 4Hardware, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Test Setup
    3. 4.3 Test Results
      1. 4.3.1 Discrete Buck Regulator (VCCINT)
        1. 4.3.1.1 0V8
      2. 4.3.2 Buck Regulators (Integrated)
        1. 4.3.2.1 1V2
        2. 4.3.2.2 1V2_VCCO
        3. 4.3.2.3 1V2_MEM
        4. 4.3.2.4 2V5_DDR_VPP
        5. 4.3.2.5 3V3_VCCO
      3. 4.3.3 Linear Regulators
        1. 4.3.3.1 0V6_VTT
        2. 4.3.3.2 0V92
        3. 4.3.3.3 1V5_GTY
        4. 4.3.3.4 1V5
        5. 4.3.3.5 5V0_SYS
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 Layout Prints
    2. 5.2 Documentation Support
    3. 5.3 Support Resources
    4. 5.4 Trademarks
  12. 6About the Author

3.4.3 VCCINT Discharge Circuit

Similar to many of the auxiliary rails, the 0V8 (VCCINT) core rail also requires an active discharge to shutdown within the required time. However, due to the large capacitance on this rail, the TPS7H2221-SEP design does not discharge the rail in a sufficient time.

Instead, an inverter and a GaN FET is used to discharge this rail. A resistor is used to prevent large current peaks during this discharge. Figure 3-29 shows the schematic and Figure 3-30 shows the layout.

TIDA-050088 VCCINT Discharge Schematic Figure 3-29 VCCINT Discharge Schematic
TIDA-050088 VCCINT Discharge Layout Figure 3-30 VCCINT Discharge Layout