AD8128_15 Datasheet, PDF (1/12 Pages) Analog Devices – CAT-5 Receiver with Adjustable Line Equalization

FEATURES
Tuned to compensate for Category-5 (CAT-5) cable losses
Up to 100 meters @ 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) @ 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
CAT-5 Receiver with
Adjustable Line Equalization
AD8128
FUNCTIONAL BLOCK DIAGRAM
AD8128
HPF
V_IN+
V_IN–
HPF
LPF
V_PEAK V_GAIN
V_OFFSET
Figure 1.
V_OUT
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 VPEAK pin, which controls the
amount of high frequency peaking. VGAIN adjusts the broadband
gain from 0 dB to 3 dB, compensating for the resistive cable
loss. VOFFSET 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 AD8128s 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.
Rev. 0
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