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

1 Features

  • Single Cell LiFePO4 Charging Algorithm
  • 30V Input Rating, With 10.5 V Overvoltage Protection (OVP)
  • 50mA Integrated Low Dropout Linear Regulator (LDO)
  • Programmable Charge Current Through ISET and EN Terminals
  • 7% Charge Current Regulation Accuracy
  • Thermal Regulation and Protection
  • Soft-Start Feature to Reduce Inrush Current
  • Battery NTC Monitoring
  • Charging Status Indication

2 Applications

  • Smart Phones
  • Mobile Phones
  • Portable Media Players
  • Low Power Handheld Devices

3 Description

The bq25071 is a highly integrated, linear, LiFePO4 battery charger targeted at space-limited portable applications. It accepts power from either a USB port or AC adapter and charges a single-cell LiFePO4 battery with up to 1 A of charge current. The 30 V input rating with 10.5 V input overvoltage protection supports low-cost unregulated adapters.

The bq25071 has a single power output that simultaneously charges the battery and powers the system. The input current is programmable from 100 mA up to 1 A using the ISET input or configurable for USB500. There is also a 4.9 V ±10% 50 mA LDO integrated into the IC for supplying low power external circuitry.

The LiFePO4 charging algorithm removes the current taper typically seen as part of the constant voltage mode control used in Li-Ion battery charge cycles which reduces charge time significantly. Instead, the battery is fast charged to the overcharge voltage and then allowed to relax to a lower float charge voltage threshold. The charger integrates the power stage with the charge current and voltage sense to achieve a high level of accuracy in the current and voltage regulation loops. An internal control loop monitors the IC junction temperature through the charge cycle and reduces the charge current if an internal temperature threshold is exceeded.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
bq25071 WSON (10) 2.00mm x 3.00mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

4 Application Schematic

fp_app_sch_lusbk6.gif