SNVSB23 March   2018 LP87521-Q1 , LP87522-Q1 , LP87523-Q1 , LP87524-Q1 , LP87525-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Simplified Schematic
  3. 3 Description
    1.     Efficiency vs Output Current
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 I2C Serial Bus Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Descriptions
      1. 8.3.1 Multi-Phase DC/DC Converters
        1. 8.3.1.1 Overview
        2. 8.3.1.2 Multiphase Operation, Phase Adding, and Phase-Shedding
        3. 8.3.1.3 Transition Between PWM and PFM Modes
        4. 8.3.1.4 Multiphase Switcher Configurations
        5. 8.3.1.5 Buck Converter Load-Current Measurement
        6. 8.3.1.6 Spread-Spectrum Mode
      2. 8.3.2 Sync Clock Functionality
      3. 8.3.3 Power-Up
      4. 8.3.4 Regulator Control
        1. 8.3.4.1 Enabling and Disabling Regulators
        2. 8.3.4.2 Changing Output Voltage
      5. 8.3.5 Enable and Disable Sequences
      6. 8.3.6 Device Reset Scenarios
      7. 8.3.7 Diagnosis and Protection Features
        1. 8.3.7.1 Power-Good Information (PGOOD Pin)
        2. 8.3.7.2 Warnings for Diagnosis (Interrupt)
          1. 8.3.7.2.1 Output Power Limit
          2. 8.3.7.2.2 Thermal Warning
        3. 8.3.7.3 Protection (Regulator Disable)
          1. 8.3.7.3.1 Short-Circuit and Overload Protection
          2. 8.3.7.3.2 Overvoltage Protection
          3. 8.3.7.3.3 Thermal Shutdown
        4. 8.3.7.4 Fault (Power Down)
          1. 8.3.7.4.1 Undervoltage Lockout
      8. 8.3.8 GPIO Signal Operation
      9. 8.3.9 Digital Signal Filtering
    4. 8.4 Device Functional Modes
      1. 8.4.1 Modes of Operation
    5. 8.5 Programming
      1. 8.5.1 I2C-Compatible Interface
        1. 8.5.1.1 Data Validity
        2. 8.5.1.2 Start and Stop Conditions
        3. 8.5.1.3 Transferring Data
        4. 8.5.1.4 I2C-Compatible Chip Address
        5. 8.5.1.5 Auto-Increment Feature
    6. 8.6 Register Maps
      1. 8.6.1 Register Descriptions
        1. 8.6.1.1  OTP_REV
        2. 8.6.1.2  BUCK0_CTRL1
        3. 8.6.1.3  BUCK1_CTRL1
        4. 8.6.1.4  BUCK2_CTRL1
        5. 8.6.1.5  BUCK3_CTRL1
        6. 8.6.1.6  BUCK0_VOUT
        7. 8.6.1.7  BUCK0_FLOOR_VOUT
        8. 8.6.1.8  BUCK1_VOUT
        9. 8.6.1.9  BUCK1_FLOOR_VOUT
        10. 8.6.1.10 BUCK2_VOUT
        11. 8.6.1.11 BUCK2_FLOOR_VOUT
        12. 8.6.1.12 BUCK3_VOUT
        13. 8.6.1.13 BUCK3_FLOOR_VOUT
        14. 8.6.1.14 BUCK0_DELAY
        15. 8.6.1.15 BUCK1_DELAY
        16. 8.6.1.16 BUCK2_DELAY
        17. 8.6.1.17 BUCK3_DELAY
        18. 8.6.1.18 GPIO2_DELAY
        19. 8.6.1.19 GPIO3_DELAY
        20. 8.6.1.20 RESET
        21. 8.6.1.21 CONFIG
        22. 8.6.1.22 INT_TOP1
        23. 8.6.1.23 INT_TOP2
        24. 8.6.1.24 INT_BUCK_0_1
        25. 8.6.1.25 INT_BUCK_2_3
        26. 8.6.1.26 TOP_STAT
        27. 8.6.1.27 BUCK_0_1_STAT
        28. 8.6.1.28 BUCK_2_3_STAT
        29. 8.6.1.29 TOP_MASK1
        30. 8.6.1.30 TOP_MASK2
        31. 8.6.1.31 BUCK_0_1_MASK
        32. 8.6.1.32 BUCK_2_3_MASK
        33. 8.6.1.33 SEL_I_LOAD
        34. 8.6.1.34 I_LOAD_2
        35. 8.6.1.35 I_LOAD_1
        36. 8.6.1.36 PGOOD_CTRL1
        37. 8.6.1.37 PGOOD_CTRL2
        38. 8.6.1.38 PGOOD_FLT
        39. 8.6.1.39 PLL_CTRL
        40. 8.6.1.40 PIN_FUNCTION
        41. 8.6.1.41 GPIO_CONFIG
        42. 8.6.1.42 GPIO_IN
        43. 8.6.1.43 GPIO_OUT
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Inductor Selection
        2. 9.2.1.2 Input Capacitor Selection
        3. 9.2.1.3 Output Capacitor Selection
        4. 9.2.1.4 Snubber Components
        5. 9.2.1.5 Supply Filtering Components
        6. 9.2.1.6 Current Limit vs. Maximum Output Current
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

9.2.1.2 Input Capacitor Selection

The input capacitors CIN0, CIN1, CIN2, and CIN3 are shown in theTypical Applications. A ceramic input bypass capacitor of 10 μF is required for each phase of the regulator. Place the input capacitor as close as possible to the VIN_Bx pin and PGND_Bx pin of the device. A larger value or higher voltage rating improves the input voltage filtering. Use X7R type of capacitors, not Y5V or F. DC bias characteristics capacitors must be considered. The minimum effective input capacitance to make sure performance is good is 1.9 μF for each buck input at the maximum input voltage including tolerances and ambient temperature range. This value assumes that at least 22 μF of additional capacitance is common for all the power input pins on the system power rail. See Table 11.

The input filter capacitor supplies current to the high-side FET switch in the first half of each cycle and decreases voltage ripple imposed on the input power source. A ceramic capacitor's low ESR provides the best noise filtering of the input voltage spikes due to this rapidly changing current. Select an input filter capacitor with sufficient ripple current rating. In addition ferrite can be used in front of the input capacitor to decrease the EMI.

Table 11. Recommended Input Capacitors (X7R Dielectric)

MANUFACTURER PART NUMBER VALUE CASE SIZE DIMENSIONS L × W × H (mm) VOLTAGE RATING (V)
Murata GCM21BR71A106KE22 10 µF (10%) 0805 2 × 1.25 × 1.25 10 V