ZHCSEN4E September 2015 – April 2018 LMK03318
PRODUCTION DATA.
The primary reference can support differential or single-ended clocks. The secondary reference can support differential or single-ended clocks or crystal. The differential input buffers on both primary and secondary support internal 50 Ω to ground or 100 Ω termination between P and N followed by on-chip AC-coupling capacitors to internal self-biased circuitry. Internal biasing is offered before the on-chip AC-coupling capacitors when the clock inputs are AC coupled externally, and this is enabled by setting R29.0 = 1 (for primary reference) or R29.1 = 1 (for secondary reference). When the clock inputs are DC coupled, the internal biasing before the on-chip AC-coupling capacitors is disabled by settings R29.0 = 0 (for primary reference) or R29.1 = 0 (for secondary reference). Figure 45 shows the differential input buffer termination options implemented on both primary and secondary and the switches (SWLVDS, SWHCSL, SWAC) are controlled by R29[5-0]. Table 4 shows the primary and secondary buffer configuration matrix for LVPECL, CML, LVDS, HCSL and LVCMOS inputs.
R50.5 / R50.7 | R50.4 / R50.6 | R29.4 / R29.5 | R29.2 / R29.3 | R29.0 / R29.1 | MODE | EXTERNAL COUPLING | TERMINATION | BIASING |
---|---|---|---|---|---|---|---|---|
0 | 1 | 0 | 1 | 1 | HCSL | AC | Internal | Internal |
0 | 1 | 0 | 1 | 1 | LVDS | AC | Internal | Internal |
0 | 1 | 0 | 1 | 1 | LVPECL | AC | Internal | Internal |
0 | 1 | 0 | 1 | 1 | CML | AC | Internal | Internal |
0 | 1 | 1 | 0 | 0 | HCSL | DC | Internal | External |
0 | 1 | 0 | 1 | 0 | LVDS | DC | Internal | External |
0 | 1 | 0 | 0 | 0 | LVPECL | DC | External | External |
0 | 1 | 0 | 0 | 0 | CML | DC | External | External |
0 | 0 | 0 | 0 | 0 | LVCMOS | DC | N/A | N/A |
Figure 46 through Figure 55 show recommendations for interfacing primary or secondary inputs of the LMK03318 with LVCMOS, LVPECL, LVDS, CML and HCSL drivers, respectively.
NOTE
The secondary reference accepts up to 2.6-V maximum swing when LVCMOS input option is selected.