SLUS696C June   2006  – February 2019 BQ26100

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Standard Serial Communication (SDQ) Timing
    7. 6.7 OTP Programming Specifications
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Non-Volatile Memory
      2. 7.3.2 Authentication
      3. 7.3.3 Communication and Power
    4. 7.4 Device Functional Modes
      1. 7.4.1 Profile Command
      2. 7.4.2 Sleep Mode Description
    5. 7.5 Programming
      1. 7.5.1 Communicating with the bq26100 Device
      2. 7.5.2 Memory Descriptions
        1. 7.5.2.1 Non-Volatile OTP Memory
          1. 7.5.2.1.1 General Use – Memory Function Commands 0xF0 (Read) and 0x0F (Write)
          2. 7.5.2.1.2 General Use — Memory Function Commands 0xFA (Read) and 0xAF (Write)
          3. 7.5.2.1.3 Status – Memory Function Commands 0xAA (Read) and 0x55 (Write)
            1. 7.5.2.1.3.1 PAGE LOCK (offset = D431h) [reset = 0h]
              1. Table 5. PAGE LOCK Field Descriptions
        2. 7.5.2.2 Non-Volatile EEPROM Memory
          1. 7.5.2.2.1 General Use – Memory Function Commands 0xE0 (Read) and 0x0E (Write)
      3. 7.5.3 SHA-1 Description
      4. 7.5.4 Key Programming Description
    6. 7.6 Register Maps
      1. 7.6.1 Volatile Register Memory
        1. 7.6.1.1 Message and Digest Registers – Memory Function Command 0xDD (Read) and 0x22 (Write)
        2. 7.6.1.2 Control and Version Registers – Memory Function Command 0x88 (Read) and 0x77 (Write)
          1. 7.6.1.2.1 CTRL Register (address = 0001h) [reset = 1h]
            1. Table 9. Control Register Field Descriptions
  8. 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
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.2 Authentication

The bq26100 device contains a SHA-1 engine to generate a modified version of the FIPS 180 HMAC. The authentication uses a challenge or public message transmitted from the host and a secret key stored on the bq26100 device to generate a 160-bit hash that will be unique. The contents of the challenge are unimportant, but each challenge should be generated randomly to improve the security of the authentication.

To compute the HMAC, let H designate the SHA-1 hash function, M designate the message transmitted to the bq26100 device, and KD designate the unique 128 bit device key of the device. HMAC(M) is defined as:

Equation 1. H[KD || H(KD || M)]

where

  • || symbolizes an append operation

The message, M, is appended to the device key, KD, and padded to become the input to the SHA-1 hash. The output of this first calculation is then appended to the device key, KD, padded again, and cycled through the SHA-1 hash a second time. The output is the HMAC digest value.

The secret key is stored in separate OTP available in bq26100 . The key space is split into two 64-bit spaces that can be programmed and locked at separate times, providing an opportunity to split the key between two different programming entities to ensure that no key leak can occur from a single source.