SNAA435 April   2025 CDC6C-Q1 , LMK3C0105-Q1 , LMK3H0102-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2FPD-Link REFCLK Requirements and Jitter Definitions
    1. 2.1 FPD-Link III REFCLK Requirements
    2. 2.2 FPD-Link IV REFCLK Requirements
  6. 3FPD-Link Clocking Selection Guide
  7. 4EMI Considerations
  8. 5Summary
  9. 6References

4 EMI Considerations

For automotive qualification, many systems using FPD-Link devices must comply with CISPR-25 radiated emission specifications. Although the FPD-Link SerDes link generally dominates the overall radiated emissions, the REFCLK signal can also impact system EMI performance. The CDC6C-Q1 oscillator has different slew rate options to slow down rise/fall times and reduce the impact of higher order harmonics in the emission spectrum. Similarly, the LMK3H0102-Q1 and LMK3C0105-Q1 clock generators can operate with spread spectrum clocking (SSC) enabled to reduce the radiated power emissions seen at the REFCLK frequency and the harmonics.

TI clocking devices can pass up to CISPR-25 Class 5 radiated EMI emissions performance. Testing was completed in TI's pre-compliant EMI chamber set up for CISPR-25 with antennas operating up to 1GHz. EMI compliance reports are available for the CDC6C-Q1 and LMK3C0105 CISPR-25 EMI Report device families that contain more detail about EMI performance and the testing setup.

CISPR-25 Performance Summary With TI Clocking Devices Figure 4-1 CISPR-25 Performance Summary With TI Clocking Devices