SNAS636C December   2013  – July 2021 LMK00338

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  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 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Differential Voltage Measurement Terminology
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Crystal Power Dissipation vs. RLIM
      2. 8.3.2 Clock Inputs
      3. 8.3.3 Clock Outputs
        1. 8.3.3.1 Reference Output
    4. 8.4 Device Functional Modes
      1. 8.4.1 VCC and VCCO Power Supplies
  9. 9 Power Supply Recommendations
    1. 9.1 Current Consumption and Power Dissipation Calculations
      1. 9.1.1 Power Dissipation Example: Worst-Case Dissipation
    2. 9.2 Power Supply Bypassing
      1. 9.2.1 Power Supply Ripple Rejection
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Management
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.1.1 Power Dissipation Example: Worst-Case Dissipation

This example shows how to calculate IC power dissipation for a configuration to estimate worst-case power dissipation. In this case, the maximum supply voltage and supply current values specified in Section 6.5 are used.

  • VCC = VCCO = 3.465 V. Maximum ICC and ICCO values.
  • CLKin0/CLKin0* input is selected.
  • Banks A and B are enabled: all outputs terminated with 50 Ω to GND.
  • REFout is enabled with 5-pF load.
  • TA = 85°C

Using the power calculations from the previous section and maximum supply current specifications, we can compute PTOTAL and PDEVICE.

  • From Equation 5: ICC_TOTAL = 10.5 mA + 38.5 mA + 38.5 mA + 5.5 mA = 93 mA
  • From ICCO_HCSL maximum spec: ICCO_BANK_A = ICCO_BANK_B = 84 mA
  • From Equation 7: PTOTAL = 3.465 V × (93 mA + 84 mA + 84 mA + 10 mA) = 939 mW
  • From Equation 8: PRT_HCSL = (0.92 V) 2 / 50 Ω = 16.9 mW (per output pair)
  • From Equation 9: PDEVICE = 939 mW – (8 × 16.9 mW) = 803.8 mW

In this worst-case example, the IC device will dissipate about 803.8 mW or 85.6 of the total power (939 mW), while the remaining 14.4% will be dissipated in the termination resistors (135.2 mW for 8 pairs). Based on θJA of 31.4°C/W, the estimated die junction temperature would be about 25.2°C above ambient, or 110.2°C when TA = 85°C.