SLUSBK6 July   2014

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Application Schematic
  5. 5 Revision History
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 Handling Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Input Overvoltage Protection
      2. 9.3.2 Undervoltage Lockout (UVLO)
      3. 9.3.3 External NTC Monitoring (TS)
      4. 9.3.4 50 mA LDO (LDO)
      5. 9.3.5 Charge Status Indicator (CHG)
      6. 9.3.6 Input Current Limit Control (EN)
    4. 9.4 Device Functional Modes
      1. 9.4.1 Charging Operation
        1. 9.4.1.1 Charger Operation with Minimum System Voltage Mode Enabled
        2. 9.4.1.2 Precharge Mode (V(BAT) ≤ V(LOWV))
        3. 9.4.1.3 Fast Charge Mode
      2. 9.4.2 Programmable Input Current Limit (ISET)
      3. 9.4.3 Thermal Regulation and Thermal Shutdown
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Selection of Input and Output Capacitors
        2. 10.2.2.2 Thermal Considerations
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Trademarks
    2. 13.2 Electrostatic Discharge Caution
    3. 13.3 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

12 Layout

12.1 Layout Guidelines

It is important to pay special attention to the PCB layout. The following provides some guidelines:

  • To obtain optimal performance, the decoupling capacitor from IN to GND (thermal pad) and the output filter capacitors from OUT to GND (thermal pad) should be placed as close as possible to the bq25071, with short trace runs to both IN, OUT and GND (thermal pad).
  • All low-current GND connections should be kept separate from the high-current charge or discharge paths from the battery. Use a single-point ground technique incorporating both the small signal ground path and the power ground path.
  • The high current charge paths into IN pin and from the OUT pin must be sized appropriately for the maximum charge current in order to avoid voltage drops in these traces.
  • The bq25071 is packaged in a thermally enhanced SON package. The package includes a thermal pad to provide an effective thermal contact between the IC and the printed circuit board (PCB); this thermal pad is also the main ground connection for the device. Connect the thermal pad to the PCB ground connection. Full PCB design guidelines for this package are provided in the application note entitled: QFN/SON PCB Attachment Application Note (SLUA271).

12.2 Layout Example

layout2_slusbk6.png

The bottom plane is a ground plane that is connected to the top through vias.

app_cir_lusbk6.gifFigure 14. Schematic