SNAS800B July   2021  – February 2024 LMX1204

PRODUCTION DATA  

  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 Outputs
        1. 6.3.3.1 Clock Output Buffers
        2. 6.3.3.2 Clock MUX
        3. 6.3.3.3 Clock Divider
        4. 6.3.3.4 Clock Multiplier and Filter Modes
          1. 6.3.3.4.1 General Information About the Clock Multiplier
          2. 6.3.3.4.2 State Machine Clock for the Clock Multiplier
            1. 6.3.3.4.2.1 State Machine Clock
          3. 6.3.3.4.3 Calibration for the Clock Multiplier
          4. 6.3.3.4.4 Using the x1 Clock Multiplier as a Filter
          5. 6.3.3.4.5 Lock Detect for the Clock Multiplier
      4. 6.3.4 Device Functional Modes Configurations
      5. 6.3.5 LOGICLK Output
        1. 6.3.5.1 LOGICLK Output Format
        2. 6.3.5.2 LOGICLK_DIV_PRE and LOGICLK_DIV 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 SYSREF Output Buffer for LOGICLK
        2. 6.3.6.2 SYSREF Frequency and Delay Generation
        3. 6.3.6.3 SYSREFREQ pins and SYSREFREQ_SPI Field
          1. 6.3.6.3.1 SYSREFREQ Pins Common-Mode Voltage
          2. 6.3.6.3.2 SYSREFREQ Windowing Feature
            1. 6.3.6.3.2.1 General Procedure Flowchart for SYSREF Windowing Operation
            2. 6.3.6.3.2.2 SYSREFREQ Repeater Mode With Delay Gen (Retime)
      7. 6.3.7 SYNC Feature
    4. 6.4 Device Functional Modes
  8. 7 Register Map
    1. 7.1 LMX1204 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 SYSREFREQ Input Configuration
      2. 8.1.2 Reducing SYSREF Common Mode Voltages
      3. 8.1.3 Current Consumption
      4. 8.1.4 Treatment of Unused Pins
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    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
    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

8.1.3 Current Consumption

The current consumption varies as a function of the setup condition. By adding up all the block currents shown in Table 8-3, a reasonable estimate of the current for any setup condition can be obtained.

Table 8-3 Current Consumption per Block
BLOCK CONDITION (s) CURRENT (mA)
Device Core CLK_MUX = Buffer Mode 294
CLK_MUX = Divide Mode 260
CLK_MUX = Multiply Mode SMCLK_EN=0 540
SMCLK_EN=1 560
SYSREF

SYNC

Windowing

 Core SYSREF_EN=1 80
Delay Generator Generator Mode (SYSREF_MODE=0,1) 53
Repeater Mode (SYSREF_MODE=2) 40
Windowing Circuitry Windowing Circuitry

(CLKPOS_CAPTURE_EN=1)

 SYSREF_MODE=0,1 113
SYSREF_MODE=2 0
SYSREF Pulser SYSREF_MODE=1 7
CLKOUT

(Per active clock channel)

 Core SYSREF_EN=0 25
SYSREF_EN = 1 Delay Not Used 30
Delay Used 40
Output Buffer CHx_EN = CLKOUTx_EN=1 4+6*CLKOUTx_PWR
SYSREFOUT Core SYSREFOUT_EN = CHx_EN = 1 74 + SYSREFOUTx_PWR*5
Output Buffer SYSREFOUT_EN = CHx_EN = 1

(SYSREFOUTx_PWR and SYSREFOUTx_VCM can interact which makes the output buffer current lower than the formula predicts in some cases)

 2*SYSREFOUTx_PWR + 2*SYSREFOUTx_VCM
LOGICLKOUT Core LOGIC_EN=1LOGICLKOUT_EN=1 SYSREF_EN=0 49
SYSREF_EN=1 59
Output Buffer CML(RP=50Ω) 16+1*LOGICLKOUT_PWR
LVDS 12
LVPECL 30
LOGISYSREFOUT Core LOGIC_EN=1

LOGISYSREFOUT_EN=1

 SYSREF_EN=0 0
SYSREF_EN=1 55
Output Buffer LOGIC_EN=1

LOGISYSREFOUT_EN=1

 CML(RP=50Ω) 16+1*LOGICLKOUT_PWR
LVDS 12
LVPECL 30

This device can consume a significant amount of current if all the output clocks, LOGICLK, multiplier, and multiplier are all enabled. Turning off the SYSREF output buffers when not actively sending SYSREF pulses to conserve current is recommended to mitigate current consumption.