ZHCSHN9A February 2018 – April 2018 LMK05028
PRODUCTION DATA.
The reference inputs (IN0 to IN3) can accept differential or single-ended clocks to synchronize any of the PLL channels. Each input has programmable input type, termination, and AC-coupled input biasing configurations as shown in Figure 26. Each input buffer drives the reference input mux of both DPLL blocks. The DPLL input mux can select from any of the reference inputs. Any DPLL can switch between inputs with different frequencies provided they can be divided-down to a common frequency by DPLL R dividers (DPLLy_REFx_RDIV). The reference input paths also drive the various detector blocks for reference input monitoring and validation. The selected reference of each DPLL input (before the R divider) can be routed through the TCXO/Ref bypass mux and output muxes, allowing a buffered copy of either DPLL reference input on OUT0 and/or OUT1.
Table 5 lists the reference input buffer configurations for common clock interface types.
REFx_TYPE | INPUT TYPES | INTERNAL SWITCH SETTINGS | ||
---|---|---|---|---|
INTERNAL TERM.
(S1, S2)(1) |
INTERNAL BIAS
(S3)(2) |
LVCMOS SLEW RATE DETECT (S4)(3) | ||
0h | LVDS, CML, LVPECL
(DC-coupled) |
OFF | OFF | OFF |
1h | LVDS, CML, LVPECL
(AC-coupled) |
OFF | ON (1.3 V) | OFF |
3h | LVDS, CML, LVPECL
(AC-coupled, internal 100-Ω) |
100 Ω | ON (1.3 V) | OFF |
4h | HCSL
(DC-coupled, internal 50-Ω) |
50 Ω | OFF | OFF |
8h | LVCMOS | OFF | OFF | ON |