ZHCSFH1 September   2016 LMK04208

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 修订历史记录
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Charge Pump Current Specification Definitions
      1. 7.1.1 Charge Pump Output Current Magnitude Variation Vs. Charge Pump Output Voltage
      2. 7.1.2 Charge Pump Sink Current Vs. Charge Pump Output Source Current Mismatch
      3. 7.1.3 Charge Pump Output Current Magnitude Variation vs. Ambient Temperature
    2. 7.2 Differential Voltage Measurement Terminology
  8. 8 Detailed Description
    1. 8.1 Overview
      1. 8.1.1  System Architecture
      2. 8.1.2  PLL1 Redundant Reference Inputs (CLKin0/CLKin0* and CLKin1/CLKin1*)
      3. 8.1.3  PLL1 Tunable Crystal Support
      4. 8.1.4  VCXO/Crystal Buffered Output
      5. 8.1.5  Frequency Holdover
      6. 8.1.6  Integrated Loop Filter Poles
      7. 8.1.7  Internal VCO
      8. 8.1.8  External VCO Mode
      9. 8.1.9  Clock Distribution
        1. 8.1.9.1 CLKout DIVIDER
        2. 8.1.9.2 CLKout Delay
        3. 8.1.9.3 Programmable Output Type
        4. 8.1.9.4 Clock Output Synchronization
      10. 8.1.10 0-Delay
      11. 8.1.11 Default Startup Clocks
      12. 8.1.12 Status Pins
      13. 8.1.13 Register Readback
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Inputs / Outputs
        1. 8.3.1.1 PLL1 Reference Inputs (CLKin0 and CLKin1)
        2. 8.3.1.2 PLL2 OSCin / OSCin* Port
        3. 8.3.1.3 Crystal Oscillator
      2. 8.3.2 Input Clock Switching
        1. 8.3.2.1 Input Clock Switching - Manual Mode
        2. 8.3.2.2 Input Clock Switching - Pin Select Mode
          1. 8.3.2.2.1 Pin Select Mode and Host
          2. 8.3.2.2.2 Switch Event without Holdover
          3. 8.3.2.2.3 Switch Event with Holdover
        3. 8.3.2.3 Input Clock Switching - Automatic Mode
          1. 8.3.2.3.1 Starting Active Clock
          2. 8.3.2.3.2 Clock Switch Event: PLL1 DLD
          3. 8.3.2.3.3 Clock Switch Event: PLL1 Vtune Rail
          4. 8.3.2.3.4 Clock Switch Event with Holdover
        4. 8.3.2.4 Input Clock Switching - Automatic Mode with Pin Select
          1. 8.3.2.4.1 Starting Active Clock
          2. 8.3.2.4.2 Clock Switch Event: PLL1 DLD
          3. 8.3.2.4.3 Clock Switch Event: PLL1 Vtune Rail
          4. 8.3.2.4.4 Clock Switch Event with Holdover
      3. 8.3.3 Holdover Mode
        1. 8.3.3.1 Enable Holdover
        2. 8.3.3.2 Entering Holdover
        3. 8.3.3.3 During Holdover
        4. 8.3.3.4 Exiting Holdover
        5. 8.3.3.5 Holdover Frequency Accuracy and DAC Performance
        6. 8.3.3.6 Holdover Mode - Automatic Exit of Holdover
      4. 8.3.4 PLLs
        1. 8.3.4.1 PLL1
        2. 8.3.4.2 PLL2
          1. 8.3.4.2.1 PLL2 Frequency Doubler
        3. 8.3.4.3 Digital Lock Detect
      5. 8.3.5 Status Pins
        1. 8.3.5.1 Logic Low
        2. 8.3.5.2 Digital Lock Detect
        3. 8.3.5.3 Holdover Status
        4. 8.3.5.4 DAC
        5. 8.3.5.5 PLL Divider Outputs
        6. 8.3.5.6 CLKinX_LOS
        7. 8.3.5.7 CLKinX Selected
        8. 8.3.5.8 MICROWIRE Readback
      6. 8.3.6 VCO
      7. 8.3.7 Clock Distribution
        1. 8.3.7.1 Fixed Digital Delay
        2. 8.3.7.2 Fixed Digital Delay - Example
        3. 8.3.7.3 Clock Output Synchronization (SYNC)
          1. 8.3.7.3.1 Effect of SYNC
          2. 8.3.7.3.2 Methods of Generating SYNC
          3. 8.3.7.3.3 Avoiding Clock Output Interruption Due to Sync
          4. 8.3.7.3.4 SYNC Timing
        4. 8.3.7.4 Dynamically Programming Digital Delay
          1. 8.3.7.4.1 Absolute vs. Relative Dynamic Digital Delay
          2. 8.3.7.4.2 Dynamic Digital Delay and 0-Delay Mode
          3. 8.3.7.4.3 SYNC and Minimum Step Size
          4. 8.3.7.4.4 Programming Overview
          5. 8.3.7.4.5 Internal Dynamic Digital Delay Timing
          6. 8.3.7.4.6 Other Timing Requirements
        5. 8.3.7.5 Absolute Dynamic Digital Delay
          1. 8.3.7.5.1 Absolute Dynamic Digital Delay - Example
        6. 8.3.7.6 Relative Dynamic Digital Delay
          1. 8.3.7.6.1 Relative Dynamic Digital Delay - Example
      8. 8.3.8 0-Delay Mode
    4. 8.4 Device Functional Modes
      1. 8.4.1 Mode Selection
      2. 8.4.2 Operating Modes
        1. 8.4.2.1 Dual PLL
        2. 8.4.2.2 0-Delay Dual PLL
        3. 8.4.2.3 Single PLL
        4. 8.4.2.4 0-Delay Single PLL
        5. 8.4.2.5 Clock Distribution
    5. 8.5 Programming
      1. 8.5.1 Special Programming Case for R0 to R5 for CLKoutX_DIV and CLKoutX_DDLY
        1. 8.5.1.1 Example
      2. 8.5.2 Recommended Programming Sequence
        1. 8.5.2.1 Programming Sequence Overview
      3. 8.5.3 Readback
        1. 8.5.3.1 Readback - Example
    6. 8.6 Register Maps
      1. 8.6.1 Register Map and Readback Register Map
      2. 8.6.2 Default Device Register Settings After Power On Reset
      3. 8.6.3 Register Descriptions
        1. 8.6.3.1  Registers R0 to R5
          1. 8.6.3.1.1 CLKoutX_PD, Powerdown CLKoutX Output Path
          2. 8.6.3.1.2 CLKoutX_OSCin_Sel, Clock Group Source
          3. 8.6.3.1.3 CLKoutX_ADLY_SEL, Select Analog Delay
          4. 8.6.3.1.4 CLKoutX_DDLY, Clock Channel Digital Delay
          5. 8.6.3.1.5 Reset
          6. 8.6.3.1.6 POWERDOWN
          7. 8.6.3.1.7 CLKoutX_HS, Digital Delay Half Shift
          8. 8.6.3.1.8 CLKoutX_DIV, Clock Output Divide
        2. 8.6.3.2  Registers R6 to R8
          1. 8.6.3.2.1 CLKoutX_TYPE
          2. 8.6.3.2.2 CLKoutX_ADLY
        3. 8.6.3.3  Register R10
          1. 8.6.3.3.1 OSCout_TYPE
          2. 8.6.3.3.2 EN_OSCout, OSCout Output Enable
          3. 8.6.3.3.3 OSCout_MUX, Clock Output Mux
          4. 8.6.3.3.4 PD_OSCin, OSCin Powerdown Control
          5. 8.6.3.3.5 OSCout_DIV, Oscillator Output Divide
          6. 8.6.3.3.6 VCO_MUX
          7. 8.6.3.3.7 EN_FEEDBACK_MUX
          8. 8.6.3.3.8 VCO_DIV, VCO Divider
          9. 8.6.3.3.9 FEEDBACK_MUX
        4. 8.6.3.4  Register R11
          1. 8.6.3.4.1 MODE: Device Mode
          2. 8.6.3.4.2 EN_SYNC, Enable Synchronization
          3. 8.6.3.4.3 NO_SYNC_CLKoutX
          4. 8.6.3.4.4 SYNC_MUX
          5. 8.6.3.4.5 SYNC_QUAL
          6. 8.6.3.4.6 SYNC_POL_INV
          7. 8.6.3.4.7 SYNC_EN_AUTO
          8. 8.6.3.4.8 SYNC_TYPE
          9. 8.6.3.4.9 EN_PLL2_XTAL
        5. 8.6.3.5  Register R12
          1. 8.6.3.5.1 LD_MUX
          2. 8.6.3.5.2 LD_TYPE
          3. 8.6.3.5.3 SYNC_PLLX_DLD
          4. 8.6.3.5.4 EN_TRACK
          5. 8.6.3.5.5 HOLDOVER_MODE
        6. 8.6.3.6  Register R13
          1. 8.6.3.6.1 HOLDOVER_MUX
          2. 8.6.3.6.2 HOLDOVER_TYPE
          3. 8.6.3.6.3 Status_CLKin1_MUX
          4. 8.6.3.6.4 Status_CLKin0_TYPE
          5. 8.6.3.6.5 DISABLE_DLD1_DET
          6. 8.6.3.6.6 Status_CLKin0_MUX
          7. 8.6.3.6.7 CLKin_SELECT_MODE
          8. 8.6.3.6.8 CLKin_Sel_INV
          9. 8.6.3.6.9 EN_CLKinX
        7. 8.6.3.7  Register 14
          1. 8.6.3.7.1 LOS_TIMEOUT
          2. 8.6.3.7.2 EN_LOS
          3. 8.6.3.7.3 Status_CLKin1_TYPE
          4. 8.6.3.7.4 CLKinX_BUF_TYPE, PLL1 CLKinX/CLKinX* Buffer Type
          5. 8.6.3.7.5 DAC_HIGH_TRIP
          6. 8.6.3.7.6 DAC_LOW_TRIP
          7. 8.6.3.7.7 EN_VTUNE_RAIL_DET
        8. 8.6.3.8  Register 15
          1. 8.6.3.8.1 MAN_DAC
          2. 8.6.3.8.2 EN_MAN_DAC
          3. 8.6.3.8.3 HOLDOVER_DLD_CNT
          4. 8.6.3.8.4 FORCE_HOLDOVER
        9. 8.6.3.9  Register 16
          1. 8.6.3.9.1 XTAL_LVL
        10. 8.6.3.10 Register 23
          1. 8.6.3.10.1 DAC_CNT
        11. 8.6.3.11 Register 24
          1. 8.6.3.11.1 PLL2_C4_LF, PLL2 Integrated Loop Filter Component
          2. 8.6.3.11.2 PLL2_C3_LF, PLL2 Integrated Loop Filter Component
          3. 8.6.3.11.3 PLL2_R4_LF, PLL2 Integrated Loop Filter Component
          4. 8.6.3.11.4 PLL2_R3_LF, PLL2 Integrated Loop Filter Component
          5. 8.6.3.11.5 PLL1_N_DLY
          6. 8.6.3.11.6 PLL1_R_DLY
          7. 8.6.3.11.7 PLL1_WND_SIZE
        12. 8.6.3.12 Register 25
          1. 8.6.3.12.1 DAC_CLK_DIV
          2. 8.6.3.12.2 PLL1_DLD_CNT
        13. 8.6.3.13 Register 26
          1. 8.6.3.13.1 PLL2_WND_SIZE
          2. 8.6.3.13.2 EN_PLL2_REF_2X, PLL2 Reference Frequency Doubler
          3. 8.6.3.13.3 PLL2_CP_POL, PLL2 Charge Pump Polarity
          4. 8.6.3.13.4 PLL2_CP_GAIN, PLL2 Charge Pump Current
          5. 8.6.3.13.5 PLL2_DLD_CNT
          6. 8.6.3.13.6 PLL2_CP_TRI, PLL2 Charge Pump TRI-STATE
        14. 8.6.3.14 Register 27
          1. 8.6.3.14.1 PLL1_CP_POL, PLL1 Charge Pump Polarity
          2. 8.6.3.14.2 PLL1_CP_GAIN, PLL1 Charge Pump Current
          3. 8.6.3.14.3 CLKinX_PreR_DIV
          4. 8.6.3.14.4 PLL1_R, PLL1 R Divider
          5. 8.6.3.14.5 PLL1_CP_TRI, PLL1 Charge Pump TRI-STATE
        15. 8.6.3.15 Register 28
          1. 8.6.3.15.1 PLL2_R, PLL2 R Divider
          2. 8.6.3.15.2 PLL1_N, PLL1 N Divider
        16. 8.6.3.16 Register 29
          1. 8.6.3.16.1 OSCin_FREQ, PLL2 Oscillator Input Frequency Register
          2. 8.6.3.16.2 PLL2_FAST_PDF, High PLL2 Phase Detector Frequency
          3. 8.6.3.16.3 PLL2_N_CAL, PLL2 N Calibration Divider
        17. 8.6.3.17 Register 30
          1. 8.6.3.17.1 PLL2_P, PLL2 N Prescaler Divider
          2. 8.6.3.17.2 PLL2_N, PLL2 N Divider
        18. 8.6.3.18 Register 31
          1. 8.6.3.18.1 READBACK_LE
          2. 8.6.3.18.2 READBACK_ADDR
          3. 8.6.3.18.3 uWire_LOCK
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Loop Filter
        1. 9.1.1.1 PLL1
        2. 9.1.1.2 PLL2
      2. 9.1.2 Driving CLKin and OSCin Inputs
        1. 9.1.2.1 Driving CLKin Pins with a Differential Source
        2. 9.1.2.2 Driving CLKin Pins with a Single-Ended Source
      3. 9.1.3 Termination and Use of Clock Output (Drivers)
        1. 9.1.3.1 Termination for DC Coupled Differential Operation
        2. 9.1.3.2 Termination for AC Coupled Differential Operation
        3. 9.1.3.3 Termination for Single-Ended Operation
      4. 9.1.4 Frequency Planning with the LMK04208
      5. 9.1.5 PLL Programming
        1. 9.1.5.1 Example PLL2 N Divider Programming
      6. 9.1.6 Digital Lock Detect Frequency Accuracy
        1. 9.1.6.1 Minimum Lock Time Calculation Example
      7. 9.1.7 Calculating Dynamic Digital Delay Values for Any Divide
        1. 9.1.7.1 Example
      8. 9.1.8 Optional Crystal Oscillator Implementation (OSCin/OSCin*)
        1. 9.1.8.1 Examples of Phase Noise and Jitter Performance
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Device Selection
          1. 9.2.2.1.1 Clock Architect
          2. 9.2.2.1.2 Calculation Using LCM
        2. 9.2.2.2 Device Configuration
          1. 9.2.2.2.1 PLL LO Reference
          2. 9.2.2.2.2 POR Clock
        3. 9.2.2.3 PLL Loop Filter Design
          1. 9.2.2.3.1 PLL1 Loop Filter Design
          2. 9.2.2.3.2 PLL2 Loop Filter Design
        4. 9.2.2.4 Clock Output Assignment
        5. 9.2.2.5 Other Device Specific Configuration
          1. 9.2.2.5.1 Digital Lock Detect
          2. 9.2.2.5.2 Holdover
        6. 9.2.2.6 Device Programming
      3. 9.2.3 Application Curve
    3. 9.3 System Examples
      1. 9.3.1 System Level Diagram
    4. 9.4 Do's and Don'ts
      1. 9.4.1 LVCMOS Complementary vs. Non-Complementary Operation
      2. 9.4.2 LVPECL Outputs
      3. 9.4.3 Sharing MICROWIRE (SPI) Lines
  10. 10Power Supply Recommendations
    1. 10.1 Pin Connection Recommendations
      1. 10.1.1 Vcc Pins and Decoupling
        1. 10.1.1.1 Vcc2, Vcc3, Vcc10, Vcc11, Vcc12, Vcc13 (CLKout Vccs)
        2. 10.1.1.2 Vcc1 (VCO), Vcc4 (Digital), and Vcc9 (PLL2)
        3. 10.1.1.3 Vcc6 (PLL1 Charge Pump) and Vcc8 (PLL2 Charge Pump)
        4. 10.1.1.4 Vcc5 (CLKin), Vcc7 (OSCin and OSCout)
      2. 10.1.2 LVPECL Outputs
      3. 10.1.3 Unused Clock Outputs
      4. 10.1.4 Unused Clock Inputs
      5. 10.1.5 LDO Bypass
    2. 10.2 Current Consumption and Power Dissipation Calculations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 开发支持
    2. 12.2 文档支持
      1. 12.2.1 相关文档
    3. 12.3 接收文档更新通知
    4. 12.4 社区资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 Glossary
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

1 特性

  • 超低的均方根值 (RMS) 抖动性能
    • 111fs，RMS 抖动（12kHz 至 20MHz）
    • 123fs，RMS 抖动（100Hz 至 20MHz）
  • 双环路 PLLatinum™锁相环 (PLL) 架构
  • PLL1
    • 集成低噪声晶体振荡器电路
    • 输入时钟丢失时采用保持模式
      • 自动或手动触发/恢复
  • PLL2
    • 标准化锁相环 (PLL) 噪底为 –227dBc/Hz
    • 相位检测器速率最高可达 155MHz
    • OSCin 倍频器
    • 集成低噪声压控振荡器 (VCO)或外部 VCO 模式
  • 两个具有 LOS 的冗余输入时钟
    • 自动和手动切换模式
  • 50% 占空比输出分配，1 至 1045（偶数和奇数）
  • 6 路低电压正射极耦合逻辑 (LVPECL)、低压差分信令 (LVDS) 或低电压互补金属氧化物半导体 (LVCMOS) 可编程输出
  • 数字延迟：固定或可动态调节
  • 模拟延迟控制（步长为 25ps）
  • 7 路差分输出；最高可达 14 路的单端输出
    • 多达 6 个 VCXO/晶振缓冲输出
  • 时钟速率高达 1536MHz
  • 0 延迟模式
  • 加电时 3 个缺省时钟输出
  • 多模式：双 PLL、单 PLL 和时钟分配
  • 工业温度范围：-40°C 至 +85°C
  • 3.15V 至 3.45V 工作电压
  • 64 引脚超薄四方扁平无引线 (WQFN) 封装 (9.0mm × 9.0mm × 0.8mm)

2 应用

  • 数据转换器计时
  • 无线基础设施
  • 网络、同步光纤网 (SONET) 或同步数字体系 (SDH)、数字用户线路接入复用器 (DSLAM)
  • 医疗、视频、军事和航天领域
  • 测试和测量

3 说明

LMK04208 器件是一款高性能时钟调节器，具备出色的时钟抖动消除、生成和分配 等高级功能， 能够充分满足新一代系统要求。双环 PLLatinum™架构利用低噪声 VCXO 模块能够实现 111fs RMS 抖动（12kHz 至 20MHz）或采用低成本外部晶振及变容二极管实现低于 200fs 的 RMS 抖动（12kHz 至 20MHz）。

双环架构由两个高性能锁相环 (PLL)、一个低噪声晶体振荡器电路以及一个高性能压控振荡器 (VCO) 构成。第一个 PLL (PLL1) 具有低噪声抖动消除器功能，而第二个 PLL (PLL2) 执行时钟生成。PLL1 可配置为与外部 VCXO 模块配合使用，或与具有外部可调晶体和变容二极管的集成式晶体振荡器配合使用。当应用于很窄的环路带宽时，PLL1 使用 VCXO 模块或可调晶体的优异近端相位噪声（偏移低于 50kHz）清理输入时钟。PLL1 的输出将用作 PLL2 的清理输入参考，以锁定集成式 VCO。可对 PLL2 的环路带宽进行优化以清理远端相位噪声（偏移高于 50 kHz），集成式 VCO 优于 VCXO 模块或 PLL1 中使用的可调晶体。

器件信息(1)

器件型号 VCO 频率 时钟输入
LMK04208 2750MHz 至 3072MHz 2
  1. 要了解所有可用封装，请见数据表末尾的可订购产品附录。

简化电路原理图

LMK04208 simplified_schematic_snas684.gif

4 修订历史记录

日期 修订版本 注释
2016 年 9 月 * 最初发布。