Triple Differential Receiver with
200 Meter Adjustable Cable Equalization
Compensates cables to 200 meters for wideband video
All resolutions through UXGA
Fast rise and fall times
8 ns with 2 V step at 200 meters of UTP cable
37 dB peak gain at 100 MHz
Two frequency response gain adjustment pins
High frequency peaking adjustment (VPEAK)
Broadband flat gain adjustment (VGAIN)
Pole location adjustment pin (VPOLE)
Compensates for variations between cables
Can be optimized for either UTP or coaxial cable
DC output offset adjust (VOFFSET)
Low output offset voltage: 24 mV
Compensates both RGB and YPbPr
Two on-chip comparators with hysteresis
Can be used for common-mode sync extraction
Available in 40-lead, 6 mm × 6 mm LFCSP
RGB video over UTP cables
Professional video projection and distribution
The AD8124 is a triple, high speed, differential receiver and
equalizer that compensates for the transmission losses of UTP
and coaxial cables up to 200 meters in length. Various gain stages
are summed together to best approximate the inverse frequency
response of the cable. Logic circuitry inside the AD8124 controls
the gain functions of the individual stages so that the lowest
noise can be achieved at short-to-medium cable lengths. This
technique optimizes its performance for low noise, short-to-
medium range applications, while at the same time provides
the high gain bandwidth required for longer cable equalization
(up to 200 meters). Each channel features a high impedance
differential input that is ideal for interfacing directly with the cable.
FUNCTIONAL BLOCK DIAGRAM
VPEAK VPOLE VOFFSET VGAIN
The AD8124 has three control pins for optimal cable
compensation, as well as an output offset adjust pin. Two
voltage-controlled pins are used to compensate for different
cable lengths; the VPEAK pin controls the amount of high frequency
peaking and the VGAIN pin adjusts the broadband flat gain, which
compensates for the low frequency flat cable loss.
For added flexibility, an optional pole adjustment pin, VPOLE,
allows movement of the pole locations, allowing for the
compensation of different gauges and types of cable as well
as variations between different cables and/or equalizers. The
VOFFSET pin allows the dc voltage at the output to be adjusted,
adding flexibility for dc-coupled systems.
The AD8124 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.
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