SNAA378 January   2023 LMX1204

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Test Setup
  5. 3Measurement Results
    1. 3.1 Input/Output Return Loss
    2. 3.2 Group Delay
    3. 3.3 Phase Error Within One LMX1204 Device
    4. 3.4 Phase Error Across all LMX1204 Channels
  6. 4Conclusion
  7. 5References

4 Conclusion

The cascaded LMX1204 reference design illustrates excellent phase balance for clock distribution paramount for clocking high-speed data converters or driving transceiver local oscillator (LO) inputs. Within a given LMX1204 device, the phase error is generally within ±5 degrees. Between multiple devices, the phase error is generally within ±15 degrees.

In some applications, it can be more convenient to think about the error or mismatch between channels in terms of timing error as opposed to phase. The phase error can be converted to a time skew parameter at a given frequency using Equation 1.

Equation 1. τskew=φerr[deg]360×f

As an example, at 8 GHz, a 10-degree phase error translates to a skew error of 3.4 ps.