SNVSA55C December   2014  – January 2018 LP3907-Q1

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-Q1 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 Component Selection
          1. 9.2.2.1.1 Inductors for SW1 And SW2
            1. 9.2.2.1.1.1 Method 1:
            2. 9.2.2.1.1.2 Method 2:
          2. 9.2.2.1.2 External Capacitors
        2. 9.2.2.2 LDO Capacitor Selection
          1. 9.2.2.2.1 Input Capacitor
          2. 9.2.2.2.2 Output Capacitor
          3. 9.2.2.2.3 Capacitor Characteristics
          4. 9.2.2.2.4 Input Capacitor Selection for SW1 And SW2
          5. 9.2.2.2.5 Output Capacitor Selection for SW1, SW2
          6. 9.2.2.2.6 I2C Pullup Resistor
        3. 9.2.2.3 Operation Without I2C Interface
          1. 9.2.2.3.1 High VIN High-Load Operation
          2. 9.2.2.3.2 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 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Trademarks
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.7 Buck Converters SW1, SW2

Unless otherwise noted, VIN = 3.6 V, CIN = 10 µF, COUT = 10 µF, LOUT = 2.2-µH ceramic, and TJ = 25°C.(1)(2)(3)(4)(5)(6)
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
VFB Feedback voltage –3%(7) 3%(7)
VOUT Line regulation 2.8 V < VIN < 5.5 V
IOUT = 10 mA		 0.089 %/V
Load regulation 100 mA < IOUT < IMAX 0.0013 %/mA
Eff Efficiency Load current = 250 mA 96%
ISHDN Shutdown supply current EN is de-asserted 0.01 µA
ƒOSC Internal oscillator frequency 1.7(7) 2.1 MHz
IPEAK Buck1 peak switching current limit 1.5 A
Buck2 peak switching current limit 1
IQ(8) Quiescent current “on” No load PFM mode 33 µA
RDSON (P) Pin-pin resistance PFET 200 mΩ
RDSON (N) Pin-pin resistance NFET 180 mΩ
TON Turnon time Start up from shutdown 500 µs
CIN Input capacitor Capacitance for stability 10 µF
COUT Output capacitor Capacitance for stability 10 µF
(1) All voltages are with respect to the potential at the GND pin.
(2) Minimum (Min) and Maximum (Max) limits are ensured by design, test, or statistical analysis. Typical numbers are not ensured, but do represent the most likely norm.
(3) CIN, COUT: Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.
(4) The device maintains a stable, regulated output voltage without a load.
(5) Quiescent current is defined here as the difference in current between the input voltage source and the load at VOUT.
(6) Buck VIN ≥ VOUT + 1 V.
(7) Limits apply over the entire junction temperature range for operation, −40°C to +125°C.
(8) The IQ can be defined as the standing current of the LP3907-Q1 when the I2C bus is active and all other power blocks have been disabled with the I2C bus, or it can be defined as the I2C bus active, and the other power blocks are active under no load condition. These two values can be used by the system designer when the device is powered using a battery.