SBAS475A June   2009  – January 2023 AMC6821-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Functional Block Diagram
    2. 8.2 Feature Description
      1. 8.2.1 ADC Converter
      2. 8.2.2 Temperature Sensor
        1. 8.2.2.1 Series Resistance Cancellation
        2. 8.2.2.2 Reading Temperature Data
        3. 8.2.2.3 Temperature Out-of-Range Detection
        4. 8.2.2.4 Remote Temperature Sensor Failure Detection
      3. 8.2.3 PWM Output
      4. 8.2.4 PWM Waveform Setting
      5. 8.2.5 Fan Speed Measurement
        1. 8.2.5.1 Tach-Data Register
          1. 8.2.5.1.1 Reading the Tach Data Register
          2. 8.2.5.1.2 RPM Measurement Rate
          3. 8.2.5.1.3 Select Number of Pulses/Revolution
          4. 8.2.5.1.4 Tach Mode Selection
          5. 8.2.5.1.5 Fan RPM Out-of-Range Detection
      6. 8.2.6 Fan Failure Detection
      7. 8.2.7 FAN-FAULT Pin
      8. 8.2.8 Fan Control
        1. 8.2.8.1 THERM Pin and External Hardware Control
          1. 8.2.8.1.1 THERM Pin as an Output
          2. 8.2.8.1.2 THERM Pin as an Input
        2. 8.2.8.2 Fan Spin-Up
        3. 8.2.8.3 Normal Fan Speed Control
          1. 8.2.8.3.1 Software DCY Control Mode
          2. 8.2.8.3.2 Software-RPM Control Mode (Fan Speed Regulator)
          3. 8.2.8.3.3 Auto Temperature Fan Mode
      9. 8.2.9 Interrupt
        1. 8.2.9.1 OVR Pin
        2. 8.2.9.2 SMBALERT Pin
        3. 8.2.9.3 SMBALERT Interrupt Behavior
        4. 8.2.9.4 Handling SMBALERT Interrupts
    3. 8.3 Device Functional Modes
    4. 8.4 Programming
      1. 8.4.1 SMBus Interface
        1. 8.4.1.1 Communication Protocols
      2. 8.4.2 SMBus Alert Response Address (ARA)
      3. 8.4.3 Power-On Reset and Start Operation
    5. 8.5 Register Map
      1. 8.5.1 Register Description
        1. 8.5.1.1 Device Configuration Registers
        2. 8.5.1.2 Device Status Registers
        3. 8.5.1.3 Fan Controller Registers
        4. 8.5.1.4 Temperature Data Registers
        5. 8.5.1.5 Temperature Limit Registers
          1. 8.5.1.5.1 Tach-Data Register
          2. 8.5.1.5.2 Tach Setting Register
          3. 8.5.1.5.3 Tach Low Limit Register
          4. 8.5.1.5.4 Tach High Limit Register
  9. 9 Application and Implementation
    1. 9.1 Power Supply Recommendations
  10. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.5.1.4 Temperature Data Registers

Local Temperature Data Register Bits: [LT10:LT0]

Bits [LT10:LT0] are the newest local temperature reading.

Remote Temperature Register Bits: [RT10:RT0]

Bits [RT10:RT0] are the newest remote temperature reading.

Table 8-27 Temp-Data-LByte Register (Address 0x06, Value After Power-On or Reset = 0x00)
Bit 7 (MSB)Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0 (LSB)
LT2LT1LT0 (LSB)00RT2RT1RT0

Bits [LT2:LT0] are the three LSBs of the newest local temperature reading.

Bits [RT2:RT0] are the three LSBs of the newest remote temperature reading.

Table 8-28 Local-Temp-Data-HByte Register (Address 0x0A, Value After Power-On or Reset = 0x80, –128°C)
Bit 7 (MSB)Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0 (LSB)
LT10 (MSB)LT9LT8LT7LT6LT5LT4LT3

Bits [LT10:LT3] are the eight MSBs of the newest local temperature reading.

Table 8-29 Remote-Temp-Data-HByte Register (Address 0x0B, Value After Power-On or Reset = 0x80, –128°C)
Bit 7 (MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (LSB)
RT10 (MSB) RT9 RT8 RT7 RT6 RT5 RT4 RT3

Bits [RT10:RT3] are the eight MSBs of the newest remote temperature reading.

It is important to note that temperature can be read as an 8-bit value (with 1°C resolution) from the Temp-DATA-Hbyte register, or as an 11-bit value (with 0.125°C resolution) from the Temp-DATA-LByte and Temp-DATA-HByte registers. If only 1°C resolution is required, the temperature readings can be read back at any time and in no particular order. If the 11-bit measurement is required, this involves a two-register read for each measurement. The Temp-DATA-LByte register (0x06) should be read first. This condition causes all temperature reading registers to be frozen until the Remote-Temp-DATA-HByte Register (0x0B) is read. This architecture also prevents an MSB reading from being updated while the 3LSBs are being read, and vice versa. See the Reading Temperature Data section for details.