LMH1239

The LMH12x9 (LMH1229, LMH1239) is a long reach adaptive cable equalizer with integrated reclocker, dual outputs, and 75Ω loop-through output. The device is designed to equalize data transmitted over 75Ω coaxial cable and operates across SMPTE data rates ranging from 125Mbps to 11.88Gbps.

The adaptive equalizer at the SDI input enables automatic loss compensation for up to 100m Belden 1694A cable reach in 4K/8K video applications where 12G-SDI (11.88Gbps) is used. The integrated reclocker attenuates high frequency jitter and fully regenerates the data using a clean, low-jitter clock. The loop filter of the reclocker is adjustable with optional external capacitor to reduce the CDR loop bandwidth.

For routing simplicity and debug, the LMH12x9 features a 1:3 output mux consisting of two 100Ω fanouts with VOD and de-emphasis control and one 75Ω loop-through SDI output. The 75Ω loop-through output is provided to extend the signal reach or enable system-level diagnostics.

The LMH12x9 features internal integrated return loss networks that meet stringent SMPTE specifications across all data rates. The LMH12x9 also has an internal eye opening monitor and a programmable pin for CDR lock indication, input carrier detect, cable fault detection, or hardware interrupts to support system diagnostics and board bring-up.

The LMH1229 is pin compatible with the LMH1297 (12G UHD-SDI bidirectional I/O with integrated reclocker) when used in cable equalizer applications. For system-level redundancy, the LMH1239 is offered with an additional integrated SDI input mux.