SNVSAT4A September   2017  – June 2021 LP873220-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 Parameters
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  DC/DC Converters
        1. 7.3.1.1 Overview
        2. 7.3.1.2 Transition Between PWM and PFM Modes
        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  Low-Dropout Linear Regulators (LDOs)
      4. 7.3.4  Power-Up
      5. 7.3.5  Regulator Control
        1. 7.3.5.1 Enabling and Disabling Regulators
        2. 7.3.5.2 Changing Output Voltage
      6. 7.3.6  Enable and Disable Sequences
      7. 7.3.7  Device Reset Scenarios
      8. 7.3.8  Diagnosis and Protection Features
        1. 7.3.8.1 Power-Good Information (PGOOD pin)
          1. 7.3.8.1.1 PGOOD Pin Gated Mode
          2. 7.3.8.1.2 PGOOD Pin Continuous Mode
          3. 7.3.8.1.3 PGOOD Pin Inactive Mode
        2. 7.3.8.2 Warnings for Diagnosis (Interrupt)
          1. 7.3.8.2.1 Output Power Limit
          2. 7.3.8.2.2 Thermal Warning
        3. 7.3.8.3 Protection (Regulator Disable)
          1. 7.3.8.3.1 Short-Circuit and Overload Protection
          2. 7.3.8.3.2 Overvoltage Protection
          3. 7.3.8.3.3 Thermal Shutdown
        4. 7.3.8.4 Fault (Power Down)
          1. 7.3.8.4.1 Undervoltage Lockout
      9. 7.3.9  Operation of the GPO Signals
      10. 7.3.10 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. 7.6.1.1  DEV_REV
        2. 7.6.1.2  OTP_REV
        3. 7.6.1.3  BUCK0_CTRL_1
        4. 7.6.1.4  BUCK0_CTRL_2
        5. 7.6.1.5  BUCK1_CTRL_1
        6. 7.6.1.6  BUCK1_CTRL_2
        7. 7.6.1.7  BUCK0_VOUT
        8. 7.6.1.8  BUCK1_VOUT
        9. 7.6.1.9  LDO0_CTRL
        10. 7.6.1.10 LDO1_CTRL
        11. 7.6.1.11 LDO0_VOUT
        12. 7.6.1.12 LDO1_VOUT
        13. 7.6.1.13 BUCK0_DELAY
        14. 7.6.1.14 BUCK1_DELAY
        15. 7.6.1.15 LDO0_DELAY
        16. 7.6.1.16 LDO1_DELAY
        17. 7.6.1.17 GPO_DELAY
        18. 7.6.1.18 GPO2_DELAY
        19. 7.6.1.19 GPO_CTRL
        20. 7.6.1.20 CONFIG
        21. 7.6.1.21 PLL_CTRL
        22. 7.6.1.22 PGOOD_CTRL_1
        23. 7.6.1.23 PGOOD_CTRL_2
        24. 7.6.1.24 PG_FAULT
        25. 7.6.1.25 RESET
        26. 7.6.1.26 INT_TOP_1
        27. 7.6.1.27 INT_TOP_2
        28. 7.6.1.28 INT_BUCK
        29. 7.6.1.29 INT_LDO
        30. 7.6.1.30 TOP_STAT
        31. 7.6.1.31 BUCK_STAT
        32. 7.6.1.32 LDO_STAT
        33. 7.6.1.33 TOP_MASK_1
        34. 7.6.1.34 TOP_MASK_2
        35. 7.6.1.35 BUCK_MASK
        36. 7.6.1.36 LDO_MASK
        37. 7.6.1.37 SEL_I_LOAD
        38. 7.6.1.38 I_LOAD_2
        39. 7.6.1.39 I_LOAD_1
  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 Buck Input Capacitor Selection
        3. 8.2.1.3 Buck Output Capacitor Selection
        4. 8.2.1.4 LDO Input Capacitor Selection
        5. 8.2.1.5 LDO Output Capacitor Selection
      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 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.5.1 Enabling and Disabling Regulators

The regulators can be enabled when the device is in STANDBY or ACTIVE state. There are two ways to enable and disable the buck regulators:

  • Using the BUCKx_EN bit in the BUCKx_CTRL_1 register (the BUCKx_EN_PIN_CTRL bit is 0 in the BUCKx_CTRL_1 register).
  • Using the EN control pin (the BUCKx_EN bit and the BUCKx_EN_PIN_CTRL bit is 1).

Similarly, there are two ways to enable and disable the LDO regulators:

  • Using the LDOx_EN bit in the LDOx_CTRL register (the LDOx_EN_PIN_CTRL bit is 0 in the LDOx_CTRL register).
  • Using the EN control pin (the LDOx_EN bit is 1 and the LDOx_EN_PIN_CTRL bit is 1).

If the EN control pin is used for enable and disable, then the following occurs:

  • The delay from the control signal rising edge to start-up is set by the BUCKx_STARTUP_DELAY[3:0] bits in the BUCKx_DELAY register and the LDOx_STARTUP_DELAY[3:0] bits in the LDOx_DELAY register.
  • The delay from the control signal falling edge to shutdown is set by the BUCKx_SHUTDOWN_DELAY[3:0] bits in the BUCKx_DELAY register and the LDOx_SHUTDOWN_DELAY[3:0] bits in the LDOx_DELAY register.
The delays are only valid for the EN signal transitions and not for control with I2C writings to the BUCKx_EN and the LDOx_EN bits.

The control of the regulator (with 0-ms delays) is shown in Table 7-3.

Table 7-3 Regulator Control
BUCKx_EN AND
LDOx_EN		BUCKx_EN_PIN_CTRL AND
LDOx_EN_PIN_CTRL		EN PINBUCKx OUTPUT VOLTAGE AND
LDOx OUTPUT VOLTAGE
Enable and disable control with the BUCKx_EN and the LDOx_EN bit0Don't CareDon't CareDisabled
10Don't CareBUCKx_VSET[7:0] and LDOx_VSET[4:0]
Enable and disable control with the EN pin11LowDisabled
11HighBUCKx_VSET[7:0] and LDOx_VSET[4:0]

The buck regulator is enabled by the EN pin or by I2C writing as shown in Figure 7-4. The soft-start circuit limits the in-rush current during start-up. When the output voltage rises to a 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 the 0.35-V level in 1 ms or the output voltage drops below 0.35-V level during operation (for minimum of 1 ms), then the regulator is disabled, and the BUCKx_SC_INT interrupt in the INT_BUCK register is set. When the output voltage reaches the Power-Good threshold level, the BUCKx_PG_INT interrupt flag in the INT_BUCK register is set. The Power-Good interrupt flag, when reaching valid output voltage, can be masked using the BUCKx_PGR_MASK bit in the BUCK_MASK register. The Power-Good interrupt flag can also be generated when the output voltage becomes invalid. The interrupt mask for invalid output voltage detection is set by the BUCKx_PGF_MASK bit in the BUCK_MASK register. A BUCKx_PG_STAT bit in the BUCK_STAT register always shows the validity of the output voltage; 1 means valid and 0 means invalid output voltage. A PGOOD_WINDOW_BUCK bit in the PGOOD_CTRL_1 register sets the detection method for the valid buck output voltage, either undervoltage detection or undervoltage and overvoltage detection.

GUID-55E1021E-DE55-4F97-A034-161A58653710-low.gifFigure 7-4 Buck Regulator Enable and Disable

The LDO regulator is enabled by the EN pin or by I2C writing, as shown in Figure 7-5. The soft-start circuit limits the in-rush current during start-up. The output voltage increase rate is less than 100 mV/μsec during soft-start. If there is a short circuit at the output, and the output voltage does not increase above the 0.3-V level in 1 ms or the output voltage drops below 0.3-V level during operation (for minimum of 1 ms), then the regulator is disabled, and the LDOx_SC_INT interrupt in the INT_LDO register is set. When the output voltage reaches the Power-Good threshold level, the LDOx_PG_INT interrupt flag in the INT_LDO register is set. The Power-Good interrupt flag, when reaching valid output voltage, can be masked using the LDOx_PGR_MASK bit in the LDO_MASK register. The Power-Good interrupt flag can also be generated when the output voltage becomes invalid. The interrupt mask for invalid output voltage detection is set by the LDOx_PGF_MASK bit in the LDO_MASK register. A LDOx_PG_STAT bit in the LDO_STAT register always shows the validity of the output voltage; 1 means valid, and 0 means invalid output voltage. A PGOOD_WINDOW_LDO bit in the PGOOD_CTRL_1 register sets the detection method for the valid LDO output voltage, either undervoltage detection or undervoltage and overvoltage detection.

GUID-4DECA40C-EF7F-4188-962D-283F3B3BF97E-low.gif Figure 7-5 LDO Regulator Enable and Disable

The EN input pin has an integrated pulldown resistor. The pulldown resistor is controlled with the EN_PD bit in the CONFIG register.