SNAS850 December   2024 LMX1205

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Timing Diagram
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
      1. 6.1.1 Range of Dividers and Multiplier
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Power On Reset
      2. 6.3.2 Temperature Sensor
      3. 6.3.3 Clock Input
        1. 6.3.3.1 Clock Input Adjustable Delay
      4. 6.3.4 Clock Outputs
        1. 6.3.4.1 Clock Output Buffers
        2. 6.3.4.2 Clock Output Adjustable Delay
        3. 6.3.4.3 Clock MUX
        4. 6.3.4.4 Clock Divider
        5. 6.3.4.5 Clock Multiplier
          1. 6.3.4.5.1 General Information About the Clock Multiplier
          2. 6.3.4.5.2 State Machine Clock for the Clock Multiplier
            1. 6.3.4.5.2.1 State Machine Clock
          3. 6.3.4.5.3 Calibration for the Clock Multiplier
          4. 6.3.4.5.4 Lock Detect for the Clock Multiplier
      5. 6.3.5 LOGICLK Outputs
        1. 6.3.5.1 LOGICLK Output Format
        2. 6.3.5.2 LOGICLK Dividers
      6. 6.3.6 SYSREF
        1. 6.3.6.1 SYSREF Output Buffers
          1. 6.3.6.1.1 SYSREF Output Buffers for Main Clocks (SYSREFOUT)
          2. 6.3.6.1.2 LOGISYSREF Output Buffer
          3. 6.3.6.1.3 SYSREF Frequency and Delay Generation
          4. 6.3.6.1.4 SYSREFREQ Pins and SYSREFREQ SPI Controlled Fields
            1. 6.3.6.1.4.1 SYSREFREQ Pins Common-Mode Voltage
            2. 6.3.6.1.4.2 SYSREFREQ Windowing Feature
              1. 6.3.6.1.4.2.1 General Procedure Flowchart for SYSREF Windowing Operation
              2. 6.3.6.1.4.2.2 Other Guidance For SYSREF Windowing
              3. 6.3.6.1.4.2.3 For Glitch-Free Output
              4. 6.3.6.1.4.2.4 If Using SYNC Feature
              5. 6.3.6.1.4.2.5 SYNC Feature
      7. 6.3.7 Power-Up Timing
      8. 6.3.8 Treatment of Unused Pins
    4. 6.4 Device Functional Modes Configurations
  8. 7 Register Map
    1. 7.1 Device Registers
  9. 8 Application and Implementation
    1. 8.1 Reference
      1. 8.1.1 Typical Application
        1. 8.1.1.1 Design Requirements
        2. 8.1.1.2 Detailed Design Procedure
        3. 8.1.1.3 Application Plots
    2. 8.2 Power Supply Recommendations
    3. 8.3 Layout
      1. 8.3.1 Layout Guidelines
      2. 8.3.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
6.3.6.1.4.1 SYSREFREQ Pins Common-Mode Voltage

The SYSREFREQ_P and SYSREFREQ_N pins can be driven either AC or DC coupled. When driven AC coupled or using the internal biasing, the common-mode voltage can be adjusted with the SYSREFREQ_VCM bits.

Table 6-15 SYSREFREQ Pin Common-Mode Voltage
SYSREFREQ_VCM SYSREFREQ Input Pins CM Voltage
0 Zero offset between pins (AC coupled)
1 Pin P is biased higher than pin N (AC coupled)
2 Pin N is biased higher than pin P (AC coupled)
3 No Bias (DC Coupled)
When there is no input during the AC coupled, the common mode voltage offset have to be created to avoid the chattering at the pins. SYSREFREQ_VCM_OFFSET fields help to set the offset between the pins.
Table 6-16 SYSREFREQ Pin Common-Mode Voltage Offset
SYSREFREQ_VCM_OFFSET Common Mode Voltage Offset Between The Pins
0 25mV
1 50mV
2 100mV
3 150mV