CAT-5 Receiver with
Adjustable Line Equalization
Data Sheet
AD8128
Rev. A Document Feedback
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FEATURES
Tuned to compensate for Category-5 (CAT-5) cable losses
Up to 100 meters at 120 MHz
2 voltage controlled frequency response adjustment pins
High frequency peaking adjustment
Broadband gain adjustment
2700 V/μs slew rate
Low output noise
1.5 mV rms integrated noise (1 GHz) at 100 meters
equalized bandwidth
DC output offset adjust
Low offset voltage error: 7 mV typ
Equalized pass-band ripple ±1 dB to 70 MHz
Input: differential or single ended
Supply current: 24 mA on ±5 V
Small 8-lead 3 mm × 3 mm LFCSP
APPLICATIONS
Keyboard-video-mouse (KVM)
RGB video over unshielded twisted pair (UTP) cable receivers
Professional video projection and distribution
Security video
FUNCTIONAL BLOCK DIAGRAM
V
OFFSET
V
GAIN
V
PEAK
V
OUT
V
IN+
V
IN–
AD8128
05699-001
HPF
HPF
LPF
Figure 1.
GENERAL DESCRIPTION
The AD8128 is a high speed, differential receiver/equalizer that
compensates for the transmission losses of unshielded twisted pair
(UTP) CAT-5 cables. Various frequency dependent gain stages
are summed together to best approximate the inverse frequency
response of CAT-5/CAT-5e cable. An equalized bandwidth of
120 MHz can be achieved for 100 meters of cable.
The AD8128 can be used as a standalone receiver/equalizer or
in conjunction with the AD8143, triple differential receiver, to
provide a complete low cost solution for receiving RGB over
UTP cable in such applications as KVM.
The AD8128 has three control pins for optimal CAT-5/CAT-5e
compensation. The equalized cable length is directly proportional
to the voltage applied to the V
PEAK
pin, which controls the amount
of high frequency peaking. V
GAIN
adjusts the broadband gain
from 0 dB to 3 dB, compensating for the resistive cable loss.
V
OFFSET
allows the output to be shifted by ±2.5 V, adding
flexibility for dc-coupled systems.
Low integrated output noise and offset voltage adjust make the
AD8128 an excellent choice for dc-coupled wideband RGB-over-
CAT-5 applications. For systems where the UTP cable is longer
than 100 meters, two AD8128 devices can be cascaded to
compensate for up to 200 meters of CAT-5/CAT-5e.
The AD8128 is available in a 3 mm × 3 mm 8-lead LFCSP and
is rated to operate over the extended temperature range of
−40°C to +85°C.
