SNVS511U June   2007  – January 2018 LP3907

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
  4. 4 Revision History
  5. 5 Device Comparison Tables
  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 (Bucks)
    4. 7.4  Thermal Information
    5. 7.5  General Electrical Characteristics
    6. 7.6  Low Dropout Regulators, LDO1 And LDO2
    7. 7.7  Buck Converters SW1, SW2
    8. 7.8  I/O Electrical Characteristics
    9. 7.9  Power-On Reset (POR) Threshold/Function
    10. 7.10 I2C Interface Timing Requirements
    11. 7.11 Typical Characteristics — LDO
    12. 7.12 Typical Characteristics — Bucks
    13. 7.13 Typical Characteristics — Buck1
    14. 7.14 Typical Characteristics — Buck2
    15. 7.15 Typical Characteristics — Bucks
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 DC-DC Converters
        1. 8.3.1.1 Linear Low Dropout Regulators (LDOs)
        2. 8.3.1.2 No-Load Stability
        3. 8.3.1.3 LDO and LDO2 Control Registers
      2. 8.3.2 SW1, SW2: Synchronous Step-Down Magnetic DC-DC Converters
        1. 8.3.2.1  Functional Description
        2. 8.3.2.2  Circuit Operation Description
        3. 8.3.2.3  PWM Operation
        4. 8.3.2.4  Internal Synchronous Rectification
        5. 8.3.2.5  Current Limiting
        6. 8.3.2.6  PFM Operation
        7. 8.3.2.7  SW1, SW2 Operation
        8. 8.3.2.8  SW1, SW2 Control Registers
        9. 8.3.2.9  Soft Start
        10. 8.3.2.10 Low Dropout Operation
        11. 8.3.2.11 Flexible Power Sequencing of Multiple Power Supplies
        12. 8.3.2.12 Power-Up Sequencing Using the EN_T Function
      3. 8.3.3 Flexible Power-On Reset (Power Good with Delay)
      4. 8.3.4 Undervoltage Lockout
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
    5. 8.5 Programming
      1. 8.5.1 I2C-Compatible Serial Interface
        1. 8.5.1.1 I2C Signals
        2. 8.5.1.2 I2C Data Validity
        3. 8.5.1.3 I2C Start and Stop Conditions
        4. 8.5.1.4 Transferring Data
      2. 8.5.2 Factory Programmable Options
    6. 8.6 Register Maps
      1. 8.6.1 LP3907 Control Registers
        1. 8.6.1.1  Interrupt Status Register (ISRA) 0x02
        2. 8.6.1.2  Control 1 Register (SCR1) 0x07
        3. 8.6.1.3  EN_DLY Preset Delay Sequence After EN_T Assertion
        4. 8.6.1.4  Buck and LDO Output Voltage Enable Register (BKLDOEN) – 0x10
        5. 8.6.1.5  Buck and LDO Status Register (BKLDOSR) – 0x11
        6. 8.6.1.6  Buck Voltage Change Control Register 1 (VCCR) – 0x20
        7. 8.6.1.7  Buck1 Target Voltage 1 Register (B1TV1) – 0x23
        8. 8.6.1.8  Buck1 Target Voltage 2 Register (B1TV2) – 0x24
        9. 8.6.1.9  Buck1 Ramp Control Register (B1RC) - 0x25
        10. 8.6.1.10 Buck2 Target Voltage 1 Register (B2TV1) – 0x29
        11. 8.6.1.11 Buck2 Target Voltage 2 Register (B2TV2) – 0x2A
        12. 8.6.1.12 Buck2 Ramp Control Register (B2RC) - 0x2B
        13. 8.6.1.13 Buck Function Register (BFCR) – 0x38
        14. 8.6.1.14 LDO1 Control Register (LDO1VCR) – 0x39
        15. 8.6.1.15 LDO2 Control Register (LDO2VCR) – 0x3A
  9. 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 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Component Selection
          1. 9.2.2.2.1 Inductors for SW1 And SW2
            1. 9.2.2.2.1.1 Method 1:
            2. 9.2.2.2.1.2 Method 2:
          2. 9.2.2.2.2 External Capacitors
        3. 9.2.2.3 LDO Capacitor Selection
          1. 9.2.2.3.1 Input Capacitor
          2. 9.2.2.3.2 Output Capacitor
          3. 9.2.2.3.3 Capacitor Characteristics
          4. 9.2.2.3.4 Input Capacitor Selection for SW1 And SW2
          5. 9.2.2.3.5 Output Capacitor Selection for SW1, SW2
          6. 9.2.2.3.6 I2C Pullup Resistor
        4. 9.2.2.4 Operation Without I2C Interface
          1. 9.2.2.4.1 High VIN High-Load Operation
          2. 9.2.2.4.2 Junction Temperature
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Analog Power Signal Routing
  11. 11Layout
    1. 11.1 DSBGA Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations of WQFN Package
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Trademarks
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resources
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

3 Description

The LP3907 device is a multi-function, programmable power management unit (PMU) optimized for low-power FPGAs, microprocessors, and DSPs. This device integrates two highly efficient 1-A, 600-mA step-down DC-DC converters with dynamic voltage scaling (DVS), two 300-mA linear regulators, and a 400-kHz I2C interface to allow a host controller access to the internal control registers of the device. The LP3907 additionally features programmable power-on sequencing.

Features include programmable power-on sequencing, communication control (I2C), dynamic voltage scaling, overcurrent protection, Power Good, synchronous rectification, thermal shutdown, and undervoltage lockout. For applications requiring light loads, the high-efficiency synchronous switching buck regulators enter PFM mode and operate with reduced switching frequency and supply current to maintain high efficiency at very light loads.

Device Information(1)

PART NUMBERPACKAGEBODY SIZE (NOM)
LP3907 WQFN (24) 4.00 mm × 4.00 mm
DSBGA (25) 2.49 mm × 2.49 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.