8.2.1.2 Detailed Design Procedure
The design procedure for dual cable driver applications is as follows:
- Select a power supply that meets the DC and AC requirements in Recommended Operating Conditions.
- Choose a small 0402 surface mount ceramic capacitor for AC-coupling capacitors to maintain characteristic impedance.
- Choose a high-quality, 75-Ω BNC connector that is capable of supporting 11.88-Gbps applications. Consult a BNC supplier regarding insertion loss, impedance specifications, and recommended footprint for meeting SMPTE return loss.
- Follow detailed high-speed layout recommendations provided in Layout Guidelines to ensure optimal signal quality when interconnecting 75-Ω and 100-Ω signals to the LMH1228.
- Determine whether SPI or SMBus communication is necessary. If the LMH1228 must be programmed with settings other than what is offered by pin control, users must use SPI or SMBus Mode for additional programming.
- Configure OUT0_SEL and SDI_OUT2_SEL pins according to the desired default use case.
- Tune the SDI_VOD output amplitude control pin for optimal signal quality depending on the cable length attached at SDI_OUT1+ and SDI_OUT2+. Use register control for more tuning options if necessary.