CAT-5 Receiver with
Adjustable Line Equalization
Data Sheet
AD8128
FEATURES FUNCTIONAL BLOCK DIAGRAM
Tuned to compensate for Category-5 (CAT-5) cable losses
AD8128
Up to 100 meters at 120 MHz
HPF
2 voltage controlled frequency response adjustment pins
High frequency peaking adjustment
V
IN+
Broadband gain adjustment
V
OUT
HPF
V
IN
2700 V/s slew rate
Low output noise
1.5 mV rms integrated noise (1 GHz) at 100 meters LPF
equalized bandwidth
DC output offset adjust
V V V
PEAK GAIN OFFSET
Low offset voltage error: 7 mV typ
Figure 1.
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
GENERAL DESCRIPTION
The AD8128 is a high speed, differential receiver/equalizer that The AD8128 has three control pins for optimal CAT-5/CAT-5e
compensates for the transmission losses of unshielded twisted pair compensation. The equalized cable length is directly proportional
(UTP) CAT-5 cables. Various frequency dependent gain stages to the voltage applied to the VPEAK pin, which controls the amount
are summed together to best approximate the inverse frequency of high frequency peaking. VGAIN adjusts the broadband gain
response of CAT-5/CAT-5e cable. An equalized bandwidth of from 0 dB to 3 dB, compensating for the resistive cable loss.
120 MHz can be achieved for 100 meters of cable. V allows the output to be shifted by 2.5 V, adding
OFFSET
flexibility for dc-coupled systems.
The AD8128 can be used as a standalone receiver/equalizer or
in conjunction with the AD8143, triple differential receiver, to Low integrated output noise and offset voltage adjust make the
provide a complete low cost solution for receiving RGB over AD8128 an excellent choice for dc-coupled wideband RGB-over-
UTP cable in such applications as KVM. 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
40C to +85C.
Rev. A Document Feedback
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05699-001AD8128 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1 Theory of Operation .........................................................................9
Applications ....................................................................................... 1 Input Common-Mode Voltage Range Considerations ............9
Functional Block Diagram .............................................................. 1 Applications Information .............................................................. 10
General Description ......................................................................... 1 KVM Applications ..................................................................... 10
Revision History ............................................................................... 2 DC Control Pins ......................................................................... 10
Specifications ..................................................................................... 3 Cascaded Applications ............................................................... 11
Absolute Maximum Ratings ............................................................ 4 Exposed Pad (EP) ....................................................................... 11
Thermal Resistance ...................................................................... 4 Layout and Power Supply Decoupling Considerations ......... 11
ESD Caution .................................................................................. 4 Evaluation Boards ...................................................................... 11
Pin Configuration and Function Descriptions ............................. 5 Outline Dimensions ....................................................................... 12
Typical Performance Characteristics ............................................. 6 Ordering Guide .......................................................................... 12
Test Circuit .................................................................................... 8
REVISION HISTORY
6/2016Rev. 0 to Rev. A
Changes to Figure 3 and Table 4 ..................................................... 5
Updated Outline Dimensions ....................................................... 12
Changes to Ordering Guide .......................................................... 12
10/2005Revision 0: Initial Version
Rev. A | Page 2 of 12