ZHCSGL2B December 2016  – June 2017 LMK62A2-100M , LMK62A2-150M , LMK62A2-156M , LMK62A2-200M , LMK62A2-266M , LMK62E0-156M , LMK62E2-156M

PRODUCTION DATA. 

  1. 特性
  2. 应用
  3. 说明
  4. 修订历史记录
  5. Pin Configuration and Functions
  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 - Power Supply
    6. 6.6 LVPECL Output Characteristics
    7. 6.7 LVDS Output Characteristics
    8. 6.8 HCSL Output Characteristics
    9. 6.9 OE Input Characteristics
    10. 6.10Frequency Tolerance Characteristics
    11. 6.11Power-On/Reset Characteristics (VDD)
    12. 6.12PSRR Characteristics
    13. 6.13PLL Clock Output Jitter Characteristics
    14. 6.14Additional Reliability and Qualification
  7. Parameter Measurement Information
    1. 7.1Device Output Configurations
  8. Power Supply Recommendations
  9. Layout
    1. 9.1Layout Guidelines
      1. 9.1.1Ensuring Thermal Reliability
      2. 9.1.2Best Practices for Signal Integrity
      3. 9.1.3Recommended Solder Reflow Profile
  10. 10器件和文档支持
    1. 10.1接收文档更新通知
    2. 10.2社区资源
    3. 10.3商标
    4. 10.4静电放电警告
    5. 10.5Glossary
  11. 11机械、封装和可订购信息

Layout

Layout Guidelines

The following sections provides recommendations for board layout, solder reflow profile and power supply bypassing when using LMK62XX to ensure good thermal / electrical performance and overall signal integrity of entire system.

Ensuring Thermal Reliability

The LMK62XX is a high-performance device. Therefore, pay careful attention to the device configuration and printed-circuit board (PCB) layout with respect to power consumption. The ground pin must be connected to the ground plane of the PCB through three vias or more, as shown in Figure 9, to maximize thermal dissipation out of the package.

Equation 1 shows the relationship between the PCB temperature around the LMK62XX and the junction temperature.

Equation 1. TB = TJ – ΨJB × P

where

  • TB: PCB temperature around the LMK62XX
  • TJ: Junction temperature of LMK62XX
  • ΨJB: Junction-to-board thermal resistance parameter of LMK62XX (64.1°C/W without airflow)
  • P: On-chip power dissipation of LMK62XX

To ensure that the maximum junction temperature of LMK62XX is below 105°C, it can be calculated that the maximum PCB temperature without airflow should be at 81°C or below when the device is optimized for best performance, resulting in maximum on-chip power dissipation of 0.36 W.

Best Practices for Signal Integrity

For best electrical performance and signal integrity of entire system with LMK62XX, TI recommends routing vias into decoupling capacitors and then into the LMK62XX. TI also recommends increasing the via count and width of the traces wherever possible. These steps ensure lowest impedance and shortest path for high frequency current flow. Figure 9 shows the layout recommendation for LMK62XX.

LMK62E2-156M LMK62E0-156M LMK62A2-100M LMK62A2-150M LMK62A2-156M LMK62A2-200M LMK62A2-266M layout_example_snas676.png Figure 9. LMK62XX Layout Recommendation for Power Supply and Ground

Recommended Solder Reflow Profile

TI recommends following the recommendations set by the solder paste supplier to optimize flux activity and to achieve proper melting temperatures of the alloy within the guidelines of J-STD-20. Processing LMK62XX with the lowest peak temperature possible while also remaining below the components peak temperature rating as listed on the MSL label is preferred. The exact temperature profile would depend on several factors including maximum peak temperature for the component as rated on the MSL label, board thickness, PCB material type, PCB geometries, component locations, sizes, densities within PCB, as well as the recommended soldering profile from the manufacturer, and capability of the reflow equipment to as confirmed by the SMT assembly operation.