ZHCSLM0A May 2020 – January 2021 LMK5B12204
PRODUCTION DATA
The reference inputs (PRIREF and SECREF) can accept differential or single-ended clocks. Each input has programmable input type, termination, and AC-coupled input biasing configurations as shown in .Each input buffer drives the reference input mux of the DPLL block. The DPLL input mux can select from any of the reference inputs. The DPLL can switch between inputs with different frequencies provided they can be divided-down to a common frequency by DPLL R dividers. The reference input paths also drive the various detector blocks for reference input monitoring and validation.
Table 9-2 lists the reference input buffer configurations for common clock interface types.
REFx_TYPE, REF_DC_MODE | INPUT TYPES | INTERNAL SWITCH SETTINGS | ||
---|---|---|---|---|
INTERNAL TERM. (S1, S2) | LVCMOS SLEW RATE DETECT (S4)(1) | LVCMOS INTERNAL AC CAPACITOR BYPASS MODE (S5)(2) | ||
0h, 0h | Differential (DC-coupled or AC-coupled) | OFF | OFF | OFF |
3h, 0h | Differential (AC-coupled, internal 100-Ω) | 100 Ω | OFF | OFF |
4h, 0h | HCSL (DC-coupled, internal 50-Ω) | 50 Ω | OFF | OFF |
8h, 0h | LVCMOS (DC-coupled, internal AC-coupling enabled) | OFF | ON | OFF |
8h, 1h | LVCMOS (DC-coupled, Internal AC-coupling disabled) | OFF | OFF | ON |
Ch, 0h | Single-ended (DC-coupled, internal 50-Ω, Internal AC-coupling enabled) | 50 Ω | ON | OFF |