SLUSFH4A March   2025  – July 2025 BQ25858-Q1 , BQ25858B-Q1

PRODUCTION DATA  

1.   1
2. 1 Features
3. 2 Applications
4. 3 Description
5. 4 Device Comparison
6. 5 Pin Configuration and Functions
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  Device Power-On-Reset
      2. 7.3.2  Device Power-Up From Battery Without Input Source
      3. 7.3.3  Device Power Up From Input Source
         1. 7.3.3.1 VAC Operating Window Programming (ACUV and ACOV)
         2. 7.3.3.2 MODE Pin Configuration
         3. 7.3.3.3 REGN Regulator (REGN LDO)
         4. 7.3.3.4 Compensation-Free Buck-Boost Converter Operation
            1. 7.3.3.4.1 Light-Load Operation
         5. 7.3.3.5 Switching Frequency and Synchronization (FSW_SYNC)
         6. 7.3.3.6 Device HIZ Mode
      4. 7.3.4  Power Management
         1. 7.3.4.1 Output Voltage Programming (VOUT_REG)
         2. 7.3.4.2 Output Current Programming (IOUT pin and IOUT_REG)
         3. 7.3.4.3 Dynamic Power Management: Input Voltage and Input Current Regulation
            1. 7.3.4.3.1 Input Current Regulation
               1. 7.3.4.3.1.1 IIN Pin
               2. 7.3.4.3.1.2 Multi-Level Current Limit (Overload Mode)
            2. 7.3.4.3.2 Input Voltage Regulation
         4. 7.3.4.4 Bypass Mode
      5. 7.3.5  Bidirectional Power Flow and Programmability
      6. 7.3.6  Switching Frequency Dithering Feature
      7. 7.3.7  Integrated 16-Bit ADC for Monitoring
      8. 7.3.8  Status Outputs (PG, STAT and INT)
         1. 7.3.8.1 Power Good Indicator (PG)
         2. 7.3.8.2 Converter Status Indicator (STAT Pin)
         3. 7.3.8.3 Interrupt to Host (INT)
      9. 7.3.9  Protections
         1. 7.3.9.1 Voltage and Current Monitoring
            1. 7.3.9.1.1 VAC Over-voltage Protection (VAC_OVP)
            2. 7.3.9.1.2 VAC Under-voltage Protection (VAC_UVP)
            3. 7.3.9.1.3 Reverse Mode Over-voltage Protection (REV_OVP)
            4. 7.3.9.1.4 Reverse Mode Under-voltage Protection (REV_UVP)
            5. 7.3.9.1.5 DRV_SUP Under-voltage and Over-voltage Protection (DRV_OKZ)
            6. 7.3.9.1.6 REGN Under-voltage Protection (REGN_OKZ)
         2. 7.3.9.2 Thermal Shutdown (TSHUT)
      10. 7.3.10 Serial Interface
          1. 7.3.10.1 Data Validity
          2. 7.3.10.2 START and STOP Conditions
          3. 7.3.10.3 Byte Format
          4. 7.3.10.4 Acknowledge (ACK) and Not Acknowledge (NACK)
          5. 7.3.10.5 Target Address and Data Direction Bit
          6. 7.3.10.6 Single Write and Read
          7. 7.3.10.7 Multi-Write and Multi-Read
   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 BQ25858-Q1/858B-Q1 Registers
9. 8 Application and Implementation
   1. 8.1 Application Information
   2. 8.2 Typical Applications
      1. 8.2.1 Typical Application (Buck-Boost configuration)
         1. 8.2.1.1 Design Requirements
         2. 8.2.1.2 Detailed Design Procedure
            1. 8.2.1.2.1 ACUV / ACOV Input Voltage Operating Window Programming
            2. 8.2.1.2.2 Switching Frequency Selection
            3. 8.2.1.2.3 Inductor Selection
            4. 8.2.1.2.4 Input (VAC) Capacitor
            5. 8.2.1.2.5 Output (VBAT) Capacitor
            6. 8.2.1.2.6 Sense Resistor (RAC_SNS and RBAT_SNS) and Current Programming
            7. 8.2.1.2.7 Converter Fast Transient Response
         3. 8.2.1.3 Application Curves
      2. 8.2.2 Typical Application (Buck-only configuration)
         1. 8.2.2.1 Design Requirements
   3. 8.3 Power Supply Recommendations
   4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
10. 9 Device and Documentation Support
    1. 9.1 Device Support
       1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
11. 10Revision History
12. 11Mechanical, Packaging, and Orderable Information

BQ25858-Q1/858B-Q1: Automotive, I²C Controlled, Bidirectional Buck-Boost Controllers with Wide Voltage Range