SLUSCQ5 October   2016

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 Timing Requirements
  7. 7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
      1. 8.1.1 Device Protection Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Device Power Up
      2. 8.3.2 Battery Switch (Q1 + Q2)
      3. 8.3.3 Integrated 10-bit ADC for Monitoring
      4. 8.3.4 Linear Regulation Mode (LDO)
      5. 8.3.5 Protection Features
        1. 8.3.5.1 Reverse Current Protection (RCP)
        2. 8.3.5.2 Internal Thermal Shutdown
        3. 8.3.5.3 IBUS and VBUS Protection
        4. 8.3.5.4 IBAT and VBAT Protection
        5. 8.3.5.5 VOUT Protection
        6. 8.3.5.6 VDROP Protection
        7. 8.3.5.7 VBUS Temperature (TS_BUS_FLT) and Battery Temperature (TS_BAT_FLT)
      6. 8.3.6 I2C Serial Interface
        1. 8.3.6.1 Data Validity
        2. 8.3.6.2 START and STOP Conditions
        3. 8.3.6.3 Byte Format
        4. 8.3.6.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.3.6.5 Slave Address and Data Direction bit
        6. 8.3.6.6 Multi-Read and Multi-Write
    4. 8.4 Device Functional Modes
    5. 8.5 I2C Register Maps
      1. 8.5.1  I2C Register Summary Table
      2. 8.5.2  REG00 (DEVICE_INFO)
      3. 8.5.3  REG01 (EVENT_1_MASK)
      4. 8.5.4  REG02 (EVENT_2_MASK)
      5. 8.5.5  REG03 (EVENT_1)
      6. 8.5.6  REG04 (EVENT_2)
      7. 8.5.7  REG05 (EVENT_1_EN)
      8. 8.5.8  REG06 (CONTROL)
      9. 8.5.9  REG07 (ADC_CONTROL)
      10. 8.5.10 REG08 (ADC_EN)
      11. 8.5.11 REG09 (PROTECTION)
      12. 8.5.12 REG0A (VBUS_OVP)
      13. 8.5.13 REG0B (VOUT_REG)
      14. 8.5.14 REG0C (VDROP_OVP)
      15. 8.5.15 REG0D (VDROP_ALM)
      16. 8.5.16 REG0E (VBAT_REG)
      17. 8.5.17 REG0F (IBAT_REG)
      18. 8.5.18 REG10 (IBUS_REG)
      19. 8.5.19 REG11 (TS_BUS_FLT)
      20. 8.5.20 REG12 (TS_BAT_FLT)
      21. 8.5.21 REG 13 and REG 14 (VBUS_ADC)
      22. 8.5.22 REG15 and REG16 (IBUS_ADC)
      23. 8.5.23 REG17 and REG18 (VOUT_ADC)
      24. 8.5.24 REG19 and REG1A (VDROP_ADC)
      25. 8.5.25 REG1B and REG1C (VBAT_ADC)
      26. 8.5.26 REG1D and REG1E (IBAT_ADC)
      27. 8.5.27 REG1F and REG20 (TS_BUS_ADC)
      28. 8.5.28 REG21 and REG22 (TS_BAT_ADC)
      29. 8.5.29 REG 23 (TDIE_ADC)
      30. 8.5.30 REG 24 (EVENT_2_EN)
      31. 8.5.31 REG 25 (EVENT_3_MASK)
      32. 8.5.32 REG 26 (EVENT_3)
      33. 8.5.33 REG 29 (CONTROL_2)
      34. 8.5.34 REG 40 (DIE_TEMP_FLT)
  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
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • YFF|42
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

A typical application consists of the device configured as an I2C controlled device and another switch mode charger for Li-Ion and Li-polymer batteries used in a wide range of smart phones and other portable devices. A host controls which charger is enabled during the charging process.

9.2 Typical Application

bq25871 tyapp_luscn1_871.gif Figure 54. bq25871 Typical Application

9.2.1 Design Requirements

Table 36. Design Requirement

PARAMETER VALUE
Input voltage range 3 V to 6 V
Input current limit 0.1 A to 7.5 A
Output voltage range 3 V to 4.975 V

9.2.2 Detailed Design Procedure

The bq25871 continuously monitors battery and adaptor connector temperature by measuring the voltage between TS_BAT pin and TS_BUS pins and ground, typically determined by a negative temperature coefficient thermistor and an external voltage divider. The device compares this voltage against its internal thresholds to determine if charging is allowed. To initiate a charging cycle, both battery and connector temperatures must be lower than the temperature threshold, else the device suspends charging and waits until both temperatures are blow the threshold.

Assuming a 103 AT NTC thermistor is used on the battery pack, the values RT1 (connected between TS_X pin to VREF) and RT2 (connected between TS_X and ground) can be determined by using the following equations.

Equation 1. bq25871 qu1_new_luscn1.gif

where

  • RTHcold and VLTF are the resistance of NTC under the cold temperature and the corresponding TS_X pin voltage when charge is allowed, RTHhot and VTCOare the resistance of NTC under the hot temperature and the corresponding TS_X pin voltage when charge is allowed.

9.2.3 Application Curves

bq25871 apc1_luscn1.gif
Figure 55. Power Up with IBUS_REG = 1 A
bq25871 apc3_luscn1.gif
1.
Figure 57. VBAT Regulation During Load Step Down
bq25871 apc5_luscn1.gif
1.
Figure 59. TS BUS OTP
bq25871 apc2_luscn1.gif
Figure 56. IBAT Regulation During Load Step Down
bq25871 apc4_luscn1.gif
1.
Figure 58. IBUS OCP During Load Transient
bq25871 apc6_luscn1.gif
1.
Figure 60. VBUS OVP with IBUS Regulation