SLUSDV2B May   2020  – January 2023 BQ25798

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD 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  Device Power-On-Reset
      2. 9.3.2  PROG Pin Configuration
      3. 9.3.3  Device Power Up from Battery without Input Source
      4. 9.3.4  Device Power Up from Input Source
        1. 9.3.4.1 Power Up REGN LDO
        2. 9.3.4.2 Poor Source Qualification
        3. 9.3.4.3 ILIM_HIZ Pin
        4. 9.3.4.4 Default VINDPM Setting
        5. 9.3.4.5 Input Source Type Detection
          1. 9.3.4.5.1 D+/D– Detection Sets Input Current Limit
          2. 9.3.4.5.2 HVDCP Detection Procedure
          3. 9.3.4.5.3 Connector Fault Detection
      5. 9.3.5  Dual-Input Power Mux
        1. 9.3.5.1 ACDRV Turn On Condition
        2. 9.3.5.2 VBUS Input Only
        3. 9.3.5.3 One ACFET-RBFET
        4. 9.3.5.4 Two ACFETs-RBFETs
      6. 9.3.6  Buck-Boost Converter Operation
        1. 9.3.6.1 Force Input Current Limit Detection
        2. 9.3.6.2 Input Current Optimizer (ICO)
        3. 9.3.6.3 Maximum Power Point Tracking for Small PV Panel
        4. 9.3.6.4 Pulse Frequency Modulation (PFM)
        5. 9.3.6.5 Device HIZ State
      7. 9.3.7  USB On-The-Go (OTG)
        1. 9.3.7.1 OTG Mode to Power External Devices
        2. 9.3.7.2 Backup Power Supply Mode
        3. 9.3.7.3 Backup Mode with Dual Input Mux
      8. 9.3.8  Power Path Management
        1. 9.3.8.1 Narrow VDC Architecture
        2. 9.3.8.2 Dynamic Power Management
      9. 9.3.9  Battery Charging Management
        1. 9.3.9.1 Autonomous Charging Cycle
        2. 9.3.9.2 Battery Charging Profile
        3. 9.3.9.3 Charging Termination
        4. 9.3.9.4 Charging Safety Timer
        5. 9.3.9.5 Thermistor Qualification
          1. 9.3.9.5.1 JEITA Guideline Compliance in Charge Mode
          2. 9.3.9.5.2 Cold/Hot Temperature Window in OTG Mode
      10. 9.3.10 Integrated 16-Bit ADC for Monitoring
      11. 9.3.11 Status Outputs ( STAT, and INT)
        1. 9.3.11.1 Charging Status Indicator (STAT Pin)
        2. 9.3.11.2 Interrupt to Host ( INT)
      12. 9.3.12 Ship FET Control
        1. 9.3.12.1 Shutdown Mode
        2. 9.3.12.2 Ship Mode
        3. 9.3.12.3 System Power Reset
      13. 9.3.13 Protections
        1. 9.3.13.1 Voltage and Current Monitoring
          1. 9.3.13.1.1  VAC Over-voltage Protection (VAC_OVP)
          2. 9.3.13.1.2  VBUS Over-voltage Protection (VBUS_OVP)
          3. 9.3.13.1.3  VBUS Under-voltage Protection (POORSRC)
          4. 9.3.13.1.4  System Over-voltage Protection (VSYS_OVP)
          5. 9.3.13.1.5  System Short Protection (VSYS_SHORT)
          6. 9.3.13.1.6  Battery Over-voltage Protection (VBAT_OVP)
          7. 9.3.13.1.7  Battery Over-current Protection (IBAT_OCP)
          8. 9.3.13.1.8  Input Over-current Protection (IBUS_OCP)
          9. 9.3.13.1.9  OTG Over-voltage Protection (OTG_OVP)
          10. 9.3.13.1.10 OTG Under-voltage Protection (OTG_UVP)
        2. 9.3.13.2 Thermal Regulation and Thermal Shutdown
      14. 9.3.14 Serial Interface
        1. 9.3.14.1 Data Validity
        2. 9.3.14.2 START and STOP Conditions
        3. 9.3.14.3 Byte Format
        4. 9.3.14.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 9.3.14.5 Target Address and Data Direction Bit
        6. 9.3.14.6 Single Write and Read
        7. 9.3.14.7 Multi-Write and Multi-Read
    4. 9.4 Device Functional Modes
      1. 9.4.1 Host Mode and Default Mode
      2. 9.4.2 Register Bit Reset
    5. 9.5 Register Map
      1. 9.5.1 I2C Registers
  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 PV Panel Selection
        2. 10.2.2.2 Inductor Selection
        3. 10.2.2.3 Input (VBUS / PMID) Capacitor
        4. 10.2.2.4 Output (VSYS) Capacitor
      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 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

12.1 Layout Guidelines

The switching nodes rising and falling times should be minimized for minimum switching loss. Proper layout of the components to minimize the high frequency current path loops (shown in the figure below) is important to prevent the electrical and magnetic field radiation and the high frequency resonant problems. Here is a PCB layout priority list for proper layout. Layout PCB according to this specific order is essential.

  1. Place the SYS output capacitors as close to SYS and GND as possible. Place a 0.1 µF small size (such as 0402 or 0201) capacitor closer than the other 10 µF capacitors. Ground connections need to be tied to the IC ground with a short copper trace connection or GND plane.
  2. Place the PMID input capacitors as close to PMID and GND as possible. Place a 0.1 µF small size (such as 0402 or 0201) capacitor closer than the other 10 µF capacitors. Ground connections need to be tied to the IC ground with a short copper trace connection or GND plane.
  3. Place the VBUS input capacitors as close to VBUS and GND as possible. Place a 0.1 µF small size (such as 0402 or 0201) capacitor closer than the other 10 µF capacitors. Ground connections need to be tied to the IC ground with a short copper trace connection or GND plane.
  4. The connection from SYS/PMID/VBUS to the 0.1 µF has to be routed on the top layer of the PCB, the returning back to GND also has to be in the top layer. Keep the whole routing loop as small as possible.
  5. Place the inductor input terminal to SW1 and the inductor output terminal to SW2 as close as possible. Minimize the copper area of this trace to lower electrical and magnetic field radiation but make the trace wide enough to carry the inductor current. Minimize parasitic capacitance from this area to any other trace or plane.
  6. Place the BAT capacitors close to BAT and GND, place the VBUS capacitors close to VBUS and GND.
  7. The REGN decoupling capacitor and the bootstrap capacitors should be placed next to the IC and make trace connection as short as possible.
  8. Ensure that there are sufficient thermal vias directly under the power MOSFETs, connecting to copper on other layers.
  9. Via size and number should be enough for a given current path.
  10. Route BATP away from switching nodes such as SW1 and SW2.

    Refer to the EVM design and more information in the BQ25792EVM, BQ25798EVM, and BQ25798BKUPEVM (BMS034) Evaluation Module for the recommended component placement with trace and via locations.

GUID-6EC5299B-E6D1-4648-A56B-0865049EFF57-low.gifFigure 12-1 Buck-Boost Converter High Frequency Current Path