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

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

8.3.4.1 Enabling and Disabling Regulators

The regulator(s) can be enabled when the device is in STANDBY or ACTIVE state. There are two ways for enable and disable the regulators:

  • Using EN_BUCKx bit in BUCKx_CTRL1 register (EN_PIN_CTRLx register bit is 0h)
  • Using EN1, EN2, EN3 control pins (EN_BUCKx bit is 1h AND EN_PIN_CTRLx register bit is 1 in BUCKx_CTRL1 register)

If the EN1, EN2, EN3 control pins are used for enable and disable then the control pin is selected with BUCKx_EN_PIN_SELECT[1:0] bits (in BUCKx_CTRL1 register). The delay from the control signal rising edge to enabling of the regulator is set by BUCKx_STARTUP_DELAY[3:0] bits, and the delay from control signal falling edge to disabling of the regulator is set by BUCKx_SHUTDOWN_DELAY[3:0] bits in BUCKx_DELAY register. The delays are valid only for EN1, EN2, EN3 signal control. The control with EN_BUCKx bit is immediate without the delays.

The control of the regulator (with 0-ms delays) is shown in Table 3.

NOTE

The control of the regulator cannot be changed from one ENx pin to a different ENx pin because the control is ENx signal-edge sensitive. The control from ENx pin to register bit and back to the original ENx pin can be done during operation.

Table 3. Regulator Control

CONTROL METHOD EN_BUCKx EN_PIN_CTRLx BUCKx_EN_PIN_SELECT[1:0] EN_ROOF_FLOOR x EN1 PIN EN2 PIN EN3 PIN BUCKx
OUTPUT VOLTAGE
Enable and disable control with EN_BUCKx bit 0h Don't Care Don't Care Don't Care Don't Care Don't Care Don't Care Disabled
1h 0h Don't Care Don't Care Don't Care Don't Care Don't Care BUCKx_VSET[7:0]
Enable and disable control with EN1 pin 1h 1h 0h 0h Low Don't Care Don't Care Disabled
1h 1h 0h 0h High Don't Care Don't Care BUCKx_VSET[7:0]
Enable and disable control with EN2 pin 1h 1h 1h 0h Don't Care Low Don't Care Disabled
1h 1h 1h 0h Don't Care High Don't Care BUCKx_VSET[7:0]
Enable and disable control with EN3 pin 1h 1h 2h 0h Don't Care Don't Care Low Disabled
1h 1h 2h 0h Don't Care Don't Care High BUCKx_VSET[7:0]
Roof and floor control with EN1 pin 1h 1h 0h 1h Low Don't Care Don't Care BUCKx_FLOOR_VSET[7:0]
1h 1h 0h 1h High Don't Care Don't Care BUCKx_VSET[7:0]
Roof and floor control with EN2 pin 1h 1h 1h 1h Don't Care Low Don't Care BUCKx_FLOOR_VSET[7:0]
1h 1h 1h 1h Don't Care High Don't Care BUCKx_VSET[7:0]
Roof and floor control with EN3 pin 1h 1h 2h 1h Don't Care Don't Care Low BUCKx_FLOOR_VSET[7:0]
1h 1h 2h 1h Don't Care Don't Care High BUCKx_VSET[7:0]

The regulator is enabled by the ENx pin or by I2C writing as shown in Figure 14. The soft-start circuit limits the in-rush current during start-up. When the output voltage rises to 0.35-V level, the output voltage becomes slew-rate controlled. If there is a short circuit at the output and the output voltage does not increase above 0.35-V level in 1 ms, the regulator is disabled, and interrupt is set. When the output voltage reaches the Power-Good threshold level the BUCKx_PG_INT interrupt flag (in INT_BUCK_x register) is set. The Power-Good interrupt flag can be masked using BUCKx_PG_MASK bit (in BUCKx_MASK register).

The ENx input pins have integrated pulldown resistors. The pulldown resistors are enabled by default, and the host can disable those with ENx_PD bits (in CONFIG register).

LP87521-Q1 LP87522-Q1 LP87523-Q1 LP87524-Q1 LP87525-Q1 Enable_Disable_LP8752_38.gifFigure 14. Regulator Enable and Disable