SNLS558C April 2017 – May 2020 LMH0397
PRODUCTION DATA.
If the LMH0397 is placed in EQ Mode (EQ/CD_SEL = L), adaptive cable equalization is enabled for SDI_IO. While the LMH0397 is in EQ Mode, IN0 EQ is powered down.
SDI_IO has an on-chip 75-Ω termination to the input common-mode voltage and includes a series return loss compensation network for meeting stringent SMPTE return loss requirements (see Figure 8). The adaptive cable equalizer is designed for AC coupling, requiring a 4.7-μF, AC-coupling capacitor for minimizing base-line wander due to the rare-occurring pathological bit pattern. The cable equalizer is designed with high gain and low noise circuitry to compensate for the insertion loss of a coaxial cable, such as Belden 1694A, which is widely used in broadcast video infrastructures.
Internal control loops are used to monitor the input signal quality and automatically select the optimal EQ boost and DC offset compensation. The LMH0397 is designed to handle the stringent pathological patterns defined in the SMPTE RP 198 and SMPTE RP 178 standards.