LMH1297

• User-configurable adaptive cable equalizer or cable driver with integrated reclocker
• Supports ST-2082-1 (12G), ST-2081-1 (6G),
  ST-424 (3G), ST-292 (HD), and ST-259 (SD)
• Compatible with DVB-ASI and AES10 (MADI)
• Integrated reclocker locks to SMPTE rates of 11.88 Gbps, 5.94 Gbps, 2.97 Gbps, 1.485 Gbps, or divide-by-1.001 sub-rates and 270 Mbps
• On-chip 75-Ω termination and return loss compensation network
• EQ (equalizer) mode:
  • Adaptive cable equalizer with integrated reclocker
  • 100-Ω Output driver with de-emphasis
  • Reclocked 75-Ω loop-through output
  • EQ mode cable reach
    (Belden 1694A, SDI_OUT disabled):
    • 75 m at 11.88 Gbps
    • 120 m at 5.94 Gbps
    • 200 m at 2.97 Gbps
    • 300 m at 1.485 Gbps
    • 600 m at 270 Mbps
• Cable driver (CD) mode:
  • Dual differential output cable drivers with integrated reclocker
  • Adaptive PCB input equalizer
  • Reclocked 100-Ω loopback output
• Automatic pre-emphasis and slew rate control on 75-Ω outputs
• Polarity inversion on 75-Ω and 100-Ω outputs
• Automatic power save in absence of input signal
  • Power dissipation: 25 mW (Typical)
• Power-down control through ENABLE pin
• Single 2.5-V Supply
  • EQ mode power dissipation: 275 mW (Typical)
  • CD mode power dissipation: 305 mW (Typical)
• Programmable through pins, SPI, or SMBus interface
• –40°C to +85°C operating temperature range
• 5-mm × 5-mm, 32-Pin QFN package

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The LMH1297 is a 12G UHD-SDI 75-Ω bidirectional I/O with integrated reclocker. This device can be configured either in input mode as an adaptive cable equalizer or in output mode as a dual cable driver, allowing system designers the flexibility to use a single BNC either as an input or output port, simplifying UHD video hardware designs. The integrated reclocker locks to all supported SMPTE data rates up to 11.88 Gbps in both modes. The bidirectional I/O has an on-chip 75-Ω termination and return loss compensation network that meets the stringent SMPTE return loss requirements.

An additional 75-Ω driver output allows the LMH1297 to support a variety of system functions. In EQ (Equalizer) Mode, this second 75-Ω driver can be used as a loop-through output. In Cable Driver (CD) Mode, this 75-Ω driver can be used as a second fan-out cable driver. The host-side 100-Ω driver can also be used as a loop-back output in CD Mode for monitoring purposes.

The on-chip reclocker attenuates high-frequency jitter and fully regenerates the data using a clean, low-jitter clock. The reclocker has a built-in loop filter and does not require any input reference clock. The LMH1297 also has an internal eye opening monitor and a programmable pin for CDR lock indication, input carrier detect, or hardware interrupts to support system diagnostics and board bring-up.

The LMH1297 is powered from a single 2.5-V supply. It is offered in a small 5-mm × 5-mm, 32-pin QFN package.