AD8122:  Triple Differential Receiver with 300m Adjustable Cable Equalization

The AD8122 is a triple, high speed, differential receiver and equalizer that compensates for the transmission losses of UTP and coaxial cables up to 300 meters in length. Various gain stages are summed together to best approximate the inverse frequency response of the cable. Each channel features a high impedance differential input that is ideal for interfacing directly with the cable.

The AD8122 has two control inputs for optimal cable compensation, one LPF control input, an input to select between UTP and coax cable, and an output offset adjust input. The cable compensation inputs are used to compensate for different cable lengths; the V_PEAK input controls the amount of high frequency peaking and the V_GAIN input adjusts the broadband flat gain, which compensates for the flat cable loss. The V_FILTER input controls the cutoff frequency of output lowpass filters on each channel. Selection between UTP and coaxial cable compensation responses is determined by the binary COAX/UTPinput, which can be left floating in UTP applications. The V_OFFSET pin allows the dc voltage at the output to be adjusted, which can be useful in dc-coupled systems.

For added flexibility, the gains of each channel can be set to x1 or x2 using the associated GAIN control pins.

The AD8122 is available in a 6 mm × 6 mm, 40-lead LFCSP and is rated to operate over the extended temperature range of −40°C to +85°C.

APPLICATIONS

• Keyboard-video-mouse (KVM)
• Digital signage
• RGB video over UTP cables
• Professional video projection and distribution
• HD video
• Security video