SLVSH48A May   2024  – September 2024 TPS7H1121-SP

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Options
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Quality Conformance Inspections
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Adjustable Output Voltage (Feedback Circuit)
      2. 8.3.2  Enable
      3. 8.3.3  Dropout Voltage VDO
      4. 8.3.4  Output Voltage Accuracy
      5. 8.3.5  Output Noise
      6. 8.3.6  Power Supply Rejection Ratio (PSRR)
      7. 8.3.7  Soft Start
      8. 8.3.8  Power Good (PG)
      9. 8.3.9  Stability
        1. 8.3.9.1 Stability
        2. 8.3.9.2 STAB Pin
      10. 8.3.10 Programmable Current Limit
      11. 8.3.11 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Enable / Disable
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Output Voltage Configuration
        2. 9.2.2.2 Output Voltage Accuracy
        3. 9.2.2.3 Enable Threshold
        4. 9.2.2.4 Soft Start Capacitor
        5. 9.2.2.5 Programmable Current Limit Resistor
        6. 9.2.2.6 Characterization of Overcurrent Events that Exceed Thermal Limits
        7. 9.2.2.7 Power Good Pull Up Resistor
        8. 9.2.2.8 Capacitors
          1. 9.2.2.8.1 Hybrid Output Capacitor Network
        9. 9.2.2.9 Frequency Compensation
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • HFT|22
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.2.3 Enable Threshold

The desired turn-on threshold is 1.35V. This means that as the VIN rail is turned-on and begins rising, the TPS7H1121 commences turning-on as soon as VIN reaches 1.35V. While this is not enough headroom from VIN to VOUT for final regulation, the regulator initiates start-up and VIN progresses to the final voltage of 5V. If desired, a higher voltage turn-on threshold can be selected (for example, 3.5V), provided the desired voltage is below 7V.

Using Equation 1 and selecting an REN(TOP) value of 49.9kΩ, the REN(BOT) can be calculated as shown in Equation 11.

Equation 11. R E N ( B O T )   =   V E N ( r i s i n g ) × R E N ( T O P ) V I N ( r i s i n g ) - V E N ( r i s i n g ) = 0.605   V   ×   49.9   k Ω 1.35   V   -   0.605   V = 40.2   k Ω

Using E192 resistor values, REN(BOT) is chosen to be 40.2kΩ.

To comply with the maximum pin voltage for Enable use Equation 4. As shown in Equation 12, VEN(final) = 2.24V which is less than the recommended maximum of 7V and above the recommended minimum final value of 0.8V.

Equation 12. VEN(final) = VIN(final)×REN(BOT)REN(BOT)+REN(TOP)=5V × 40.2kΩ40.2kΩ + 49.9kΩ =2.24V