ZHCSK16A October 2017 – July 2019 LMK04228
PRODUCTION DATA.
Both CLKin ports can be driven by differential signals. TI recommends setting the input mode to bipolar (CLKinX_BUF_TYPE = 0) when using differential reference clocks. The LMK04228 internally biases the input pins so the differential interface should be AC coupled. The recommended circuits for driving the CLKin pins with either LVDS or LVPECL are shown in Figure 9 and Figure 10.
Figure 9. CLKinX/X* Termination for an LVDS Reference Clock Source
Figure 10. CLKinX/X* Termination for an LVPECL Reference Clock Source Finally, a reference clock source that produces a differential sine wave output can drive the CLKin pins using the following circuit. Note: the signal level must conform to the requirements for the CLKin pins listed in Electrical Characteristics.
Figure 11. CLKinX/X* Termination for a Differential Sinewave Reference Clock Source