SLVSIK1 March   2026 BQ25640

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions (QFN)
  7. 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. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Power-On-Reset (POR)
      2. 7.3.2  Device Power Up from Battery
      3. 7.3.3  USB-C Detection
        1. 7.3.3.1 Legacy Adapter Detection
        2. 7.3.3.2 USB-C Dead Battery Mode
        3. 7.3.3.3 SNK Mode
        4. 7.3.3.4 SRC Mode
        5. 7.3.3.5 DRP Mode - Dual Role Port
        6. 7.3.3.6 USB-C Debug Accessory Detection
      4. 7.3.4  Device Power Up from Input Source
        1. 7.3.4.1 REGN LDO Power Up
        2. 7.3.4.2 D+/D– Detection Sets Input Current Limit
        3. 7.3.4.3 Input Voltage Limit Threshold Setting (VINDPM Threshold)
        4. 7.3.4.4 Converter Power-Up
        5. 7.3.4.5 Input Current Optimizer (ICO)
        6. 7.3.4.6 Switching Frequency and Dithering Feature
      5. 7.3.5  Power Path Management
        1. 7.3.5.1 Narrow VDC Architecture
        2. 7.3.5.2 Dynamic Power Management
        3. 7.3.5.3 High Impedance (HIZ) Mode
      6. 7.3.6  Battery Charging Management
        1. 7.3.6.1 Autonomous Charging Cycle
        2. 7.3.6.2 Battery Charging Profile
        3. 7.3.6.3 Charging Termination
        4. 7.3.6.4 Thermistor Qualification
          1. 7.3.6.4.1 Advanced Temperature Profile in Charge Mode
          2. 7.3.6.4.2 TS Pin Thermistor Configuration
          3. 7.3.6.4.3 Cold/Hot Temperature Window in OTG Mode
          4. 7.3.6.4.4 JEITA Charge Rate Scaling
        5. 7.3.6.5 Charging Safety Timers
        6. 7.3.6.6 Alternate Power from Input
      7. 7.3.7  USB On-The-Go (OTG)
        1. 7.3.7.1 Boost OTG Mode
      8. 7.3.8  Integrated 12-bit ADC for Monitoring
      9. 7.3.9  Status Outputs (INT , PG )
        1. 7.3.9.1 PG Pin Power Good Indicator
        2. 7.3.9.2 Interrupts and Status, Flag, and Mask Bits
        3. 7.3.9.3 Interrupt to Host (INT)
      10. 7.3.10 BATFET Control
        1. 7.3.10.1 Shutdown Mode
        2. 7.3.10.2 Ship Mode
        3. 7.3.10.3 Standby Mode
        4. 7.3.10.4 System Power Reset
      11. 7.3.11 Protections
        1. 7.3.11.1 Voltage and Current Monitoring in Battery Only and HIZ Modes
          1. 7.3.11.1.1 Battery Overcurrent Protection
          2. 7.3.11.1.2 Battery Undervoltage Lockout
        2. 7.3.11.2 Voltage and Current Monitoring in Buck Mode
          1. 7.3.11.2.1 Input Overvoltage
          2. 7.3.11.2.2 System Overvoltage Protection (SYSOVP)
          3. 7.3.11.2.3 Forward Converter Cycle-by-Cycle Current Limit
          4. 7.3.11.2.4 System Short
          5. 7.3.11.2.5 Battery Overvoltage Protection (BATOVP)
          6. 7.3.11.2.6 Sleep Comparator
        3. 7.3.11.3 Voltage and Current Monitoring in Boost Mode
          1. 7.3.11.3.1 Boost Mode Overvoltage Protection
          2. 7.3.11.3.2 Boost Mode Duty Cycle Protection
          3. 7.3.11.3.3 Boost Mode PMID Undervoltage Protection
          4. 7.3.11.3.4 Boost Mode Battery Undervoltage
          5. 7.3.11.3.5 Boost Converter Cycle-by-Cycle Current Limit
          6. 7.3.11.3.6 Boost Mode SYS Short
        4. 7.3.11.4 Thermal Regulation and Thermal Shutdown
          1. 7.3.11.4.1 Thermal Protection in Buck Mode
          2. 7.3.11.4.2 Thermal Protection in Boost Mode
          3. 7.3.11.4.3 Thermal Protection in Battery-only Mode
        5. 7.3.11.5 Liquid Detection and Corrosion Mitigation (Patent Pending)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Host Mode and Default Mode
      2. 7.4.2 Register Bit Reset
    5. 7.5 Programming
      1. 7.5.1 Serial Interface
        1. 7.5.1.1 Data Validity
        2. 7.5.1.2 START and STOP Conditions
        3. 7.5.1.3 Byte Format
        4. 7.5.1.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 7.5.1.5 Target Address and Data Direction Bit
        6. 7.5.1.6 Single Write and Read
        7. 7.5.1.7 Multi-Write and Multi-Read
    6. 7.6 Register Maps
      1. 7.6.1 Register Programming
      2. 7.6.2 BQ25640 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Inductor Selection
        2. 8.2.2.2 Input Capacitor
        3. 8.2.2.3 Output Capacitor
      3. 8.2.3 Application Curves
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Package Option Addendum
7.3.6.4.2 TS Pin Thermistor Configuration

The typical TS resistor network is illustrated below.

BQ25640 TS Resistor NetworkFigure 7-6 TS Resistor Network

The value of RT1 and RT2 are determined from the resistance of the recommended 103AT-2 thermistor at 0ºC and 60ºC (RTHCOLD= 27.28kΩ and RTHHOT = 3.02kΩ) and the corresponding voltage thresholds VTSCOLD and VTSHOT (expressed as percentage of REGN with value between 0 and 1).

Equation 1. RT2 = RTH COLD × RTH HOT × ( 1 VTS COLD - 1 VTS HOT ) RTH HOT × ( 1 VTS HOT - 1 ) - RTH COLD × ( 1 VTS COLD - 1 )
Equation 2. RT1 = 1 VTS COLD - 1 1 R T2 + 1 RTH COLD

Assuming a 103AT-2 NTC thermistor on the battery pack, the RT1 and RT2 are calculated to be 5.23kΩ and 30.1kΩ respectively.