ZHCSH72I September   2011  – December 2017 LMK00301


  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      功能框图
      2.      LVPECL 输出摆幅 (VOD) 与频率间的关系
  4. 修订历史记录
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
  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 Typical Characteristics
  8. Parameter Measurement Information
    1. 8.1 Differential Voltage Measurement Terminology
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
      1. 9.2.1 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 VCC and VCCO Power Supplies
      2. 9.3.2 Clock Inputs
      3. 9.3.3 Clock Outputs
        1. Reference Output
  10. 10Application and Implementation
    1. 10.1 Driving the Clock Inputs
    2. 10.2 Crystal Interface
    3. 10.3 Termination and Use of Clock Drivers
      1. 10.3.1 Termination for DC Coupled Differential Operation
      2. 10.3.2 Termination for AC Coupled Differential Operation
      3. 10.3.3 Termination for Single-Ended Operation
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Sequencing
    2. 11.2 Current Consumption and Power Dissipation Calculations
      1. 11.2.1 Power Dissipation Example #1: Separate Vcc and Vcco Supplies with Unused Outputs
      2. 11.2.2 Power Dissipation Example #2: Worst-Case Dissipation
    3. 11.3 Power Supply Bypassing
      1. 11.3.1 Power Supply Ripple Rejection
    4. 11.4 Thermal Management
  12. 12器件和文档支持
    1. 12.1 文档支持
      1. 12.1.1 相关文档
    2. 12.2 社区资源
    3. 12.3 商标
    4. 12.4 静电放电警告
    5. 12.5 Glossary
  13. 13机械、封装和可订购信息


机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)

Power Supply Ripple Rejection

In practical system applications, power supply noise (ripple) can be generated from switching power supplies, digital ASICs or FPGAs, etc. While power supply bypassing will help filter out some of this noise, it is important to understand the effect of power supply ripple on the device performance. When a single-tone sinusoidal signal is applied to the power supply of a clock distribution device, such as LMK00301, it can produce narrow-band phase modulation as well as amplitude modulation on the clock output (carrier). In the single-side band phase noise spectrum, the ripple-induced phase modulation appears as a phase spur level relative to the carrier (measured in dBc).

For the LMK00301, power supply ripple rejection, or PSRR, was measured as the single-sideband phase spur level (in dBc) modulated onto the clock output when a ripple signal was injected onto the Vcco supply. The PSRR test setup is shown in Figure 39.

LMK00301 30147040.gifFigure 39. PSRR Test Setup

A signal generator was used to inject a sinusoidal signal onto the Vcco supply of the DUT board, and the peak-to-peak ripple amplitude was measured at the Vcco pins of the device. A limiting amplifier was used to remove amplitude modulation on the differential output clock and convert it to a single-ended signal for the phase noise analyzer. The phase spur level measurements were taken for clock frequencies of 156.25 MHz and 312.5 MHz under the following power supply ripple conditions:

  • Ripple amplitude: 100 mVpp on Vcco = 2.5 V
  • Ripple frequencies: 100 kHz, 1 MHz, and 10 MHz

Assuming no amplitude modulation effects and small index modulation, the peak-to-peak deterministic jitter (DJ) can be calculated using the measured single-sideband phase spur level (PSRR) as follows:

Equation 12. DJ (ps pk-pk) = [(2*10(PSRR / 20)) / (π*fCLK)] * 1012

The “PSRR vs. Ripple Frequency” plots in Typical Characteristics show the ripple-induced phase spur levels for the differential output types at 156.25 MHz and 312.5 MHz . The LMK00301 exhibits very good and well-behaved PSRR characteristics across the ripple frequency range for all differential output types. The phase spur levels for LVPECL are below -64 dBc at 156.25 MHz and below -62 dBc at 312.5 MHz. Using Equation 12, these phase spur levels translate to Deterministic Jitter values of 2.57 ps pk-pk at 156.25 MHz and 1.62 ps pk-pk at 312.5 MHz. Testing has shown that the PSRR performance of the device improves for Vcco = 3.3 V under the same ripple amplitude and frequency conditions.