SNVSBA3 December   2020 LP875761-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 I2C Serial Bus Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Descriptions
      1. 7.3.1 Multi-Phase DC/DC Converters
        1. 7.3.1.1 Overview
        2. 7.3.1.2 Multiphase Switcher Configurations
        3. 7.3.1.3 Buck Converter Load-Current Measurement
        4. 7.3.1.4 Spread-Spectrum Mode
      2. 7.3.2 Sync Clock Functionality
      3. 7.3.3 Power-Up
      4. 7.3.4 Regulator Control
        1. 7.3.4.1 Enabling and Disabling Regulators
      5. 7.3.5 Enable and Disable Sequences
      6. 7.3.6 Device Reset Scenarios
      7. 7.3.7 Diagnosis and Protection Features
        1. 7.3.7.1 Power-Good Information (PGOOD pin)
        2. 7.3.7.2 Warnings for Diagnosis (Interrupt)
          1. 7.3.7.2.1 Output Power Limit
          2. 7.3.7.2.2 Thermal Warning
        3. 7.3.7.3 Protection (Regulator Disable)
          1. 7.3.7.3.1 Short-Circuit and Overload Protection
          2. 7.3.7.3.2 Overvoltage Protection
          3. 7.3.7.3.3 Thermal Shutdown
        4. 7.3.7.4 Fault (Power Down)
          1. 7.3.7.4.1 Undervoltage Lockout
      8. 7.3.8 GPIO Signal Operation
      9. 7.3.9 Digital Signal Filtering
    4. 7.4 Device Functional Modes
      1. 7.4.1 Modes of Operation
    5. 7.5 Programming
      1. 7.5.1 I2C-Compatible Interface
        1. 7.5.1.1 Data Validity
        2. 7.5.1.2 Start and Stop Conditions
        3. 7.5.1.3 Transferring Data
        4. 7.5.1.4 I2C-Compatible Chip Address
        5. 7.5.1.5 Auto-Increment Feature
    6. 7.6 Register Maps
      1. 7.6.1 Register Descriptions
        1.       53
        2. 7.6.1.1  DEV_REV
        3. 7.6.1.2  OTP_REV
        4. 7.6.1.3  BUCK0_CTRL1
        5. 7.6.1.4  BUCK0_CTRL2
        6. 7.6.1.5  BUCK1_CTRL2
        7. 7.6.1.6  BUCK2_CTRL2
        8. 7.6.1.7  BUCK3_CTRL2
        9. 7.6.1.8  BUCK0_DELAY
        10. 7.6.1.9  GPIO2_DELAY
        11. 7.6.1.10 GPIO3_DELAY
        12. 7.6.1.11 RESET
        13. 7.6.1.12 CONFIG
        14. 7.6.1.13 INT_TOP1
        15. 7.6.1.14 INT_TOP2
        16. 7.6.1.15 INT_BUCK_0_1
        17. 7.6.1.16 INT_BUCK_2_3
        18. 7.6.1.17 TOP_STAT
        19. 7.6.1.18 BUCK_0_1_STAT
        20. 7.6.1.19 BUCK_2_3_STAT
        21. 7.6.1.20 TOP_MASK1
        22. 7.6.1.21 TOP_MASK2
        23. 7.6.1.22 BUCK_0_1_MASK
        24. 7.6.1.23 BUCK_2_3_MASK
        25. 7.6.1.24 SEL_I_LOAD
        26. 7.6.1.25 I_LOAD_2
        27. 7.6.1.26 I_LOAD_1
        28. 7.6.1.27 PGOOD_CTRL1
        29. 7.6.1.28 PGOOD_CTRL2
        30. 7.6.1.29 PGOOD_FLT
        31. 7.6.1.30 PLL_CTRL
        32. 7.6.1.31 PIN_FUNCTION
        33. 7.6.1.32 GPIO_CONFIG
        34. 7.6.1.33 GPIO_IN
        35. 7.6.1.34 GPIO_OUT
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Inductor Selection
        2. 8.2.1.2 Input Capacitor Selection
        3. 8.2.1.3 Output Capacitor Selection
        4. 8.2.1.4 Snubber Components
        5. 8.2.1.5 Supply Filtering Components
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RNF|26
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.1.1 Overview

The LP875761-Q1 includes four step-down DC/DC converter cores which are configured as a 4-phase single output.

TheLP875761-Q1 has the following features:

  • Optional external clock input to minimize crosstalk
  • Optional spread spectrum technique to decrease EMI
  • Phase control for optimized EMI
  • Synchronous rectification
  • Current mode loop with PI compensator
  • Soft start
  • Power Good flag with maskable interrupt
  • Power Good signal (PGOOD) with selectable sources
  • Average output current sensing (for load current measurement)
  • Current balancing between the phases of the converter
  • Differential voltage sensing from point of the load for multiphase output

The following parameters can be programmed via registers:

  • Forced multiphase operation for multiphase outputs (forces also the PWM operation)
  • Peak current limit for high-side FET
  • Enable and disable delays for regulators and GPIOs controlled by ENx pins

The 4 buck converters in the LP875761-Q1 operate in forced multiphase configuration as one 4-phase converter, which offers several advantages over one power stage converter. For application processor power delivery, lower ripple on the input and output currents and faster transient response to load steps are the most significant advantages. Also, because the load current is evenly shared among multiple channels in multiphase output configuration, the heat generated is greatly decreased for each channel due to the fact that power loss is proportional to square of current. The physical size of the output inductor shrinks significantly due to this heat reduction. Figure 7-1 shows a block diagram of a single core.

Interleaving switching action of the 4-phase converter is shown in Figure 7-2. The 4-phase converter switches each channel 90° apart. As a result, the 4-phase converter has an effective ripple frequency four times greater than the switching frequency of a one phase converter

GUID-9CEBE976-AD47-425B-A12A-79AFC0A75DEB-low.gifFigure 7-1 Detailed Block Diagram Showing One Core
GUID-5D97A307-FADA-4BAB-B5D1-9345E2A6761E-low.gif
Graph is not in scale and is for illustrative purposes only.
Figure 7-2 Example of PWM Timings, Inductor Current Waveforms, and Total Output Current in 4-Phase Configuration.