AD8123ACPZ

Manufacturer Part NumberAD8123ACPZ
DescriptionTriple Equalizer
ManufacturerAnalog Devices Inc
AD8123ACPZ datasheet
 


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FEATURES
Compensates cables to 300 meters for wideband video
Fast rise and fall times
4.9 ns with 2 V step @ 150 meters of UTP cable
8.0 ns with 2 V step @ 300 meters of UTP cable
55 dB peak gain at 100 MHz
Two frequency response gain adjustment pins
High frequency peaking adjustment (V
Broadband flat gain adjustment (V
GAIN
Pole location adjustment pin (V
)
POLE
Compensates for variations between cables
Can be optimized for either UTP or coaxial cable
DC output offset adjust (V
)
OFFSET
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
APPLICATIONS
Keyboard-video-mouse (KVM)
Digital signage
RGB video over UTP cables
Professional video projection and distribution
HD video
Security video
GENERAL DESCRIPTION
The AD8123 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. Logic circuitry inside the AD8123
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 long cable equalization
(up to 300 meters). Each channel features a high impedance
differential input that is ideal for interfacing directly with the cable.
The AD8123 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 V
pin controls the amount of high frequency
PEAK
peaking and the V
pin adjusts the broadband flat gain,
GAIN
which compensates for the low frequency flat cable loss.
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
Triple Differential Receiver with
Adjustable Line Equalization
)
PEAK
)
–IN
CMP1
+IN
CMP1
–IN
CMP2
+IN
CMP2
For added flexibility, an optional pole adjustment pin, V
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
V
pin allows the dc voltage at the output to be adjusted,
OFFSET
adding flexibility for dc-coupled systems.
The AD8123 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.
UXGA RESOLUTION IMAGE
AFTER 300 METER CAT-5 CABLE
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
FUNCTIONAL BLOCK DIAGRAM
V
V
V
V
PEAK
POLE
OFFSET
GAIN
AD8123
–IN
R
+IN
R
–IN
G
+IN
G
IN
B
+IN
B
Figure 1.
UXGA RESOLUTION IMAGE
AFTER 300 METER CAT-5 CABLE
BEFORE AD8123.
AFTER AD8123.
Figure 2.
©2007 Analog Devices, Inc. All rights reserved.
AD8123
OUT
R
OUT
G
OUT
B
OUT
CMP1
OUT
CMP2
,
POLE
www.analog.com

AD8123ACPZ Summary of contents

  • Page 1

    FEATURES Compensates cables to 300 meters for wideband video Fast rise and fall times 4.9 ns with 2 V step @ 150 meters of UTP cable 8.0 ns with 2 V step @ 300 meters of UTP cable 55 dB ...

  • Page 2

    AD8123 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5 Thermal Resistance ...................................................................... 5 ESD Caution.................................................................................. 5 Pin Configuration and Function Description ...

  • Page 3

    SPECIFICATIONS T = 25° ± 150 Ω, Belden Cable (BL-7987R Figure 17, unless otherwise noted. Table 1. Parameter PEAKING PERFORMANCE (NO CABLE) Peak Frequency Peak Gain DYNAMIC PERFORMANCE 10% to 90% ...

  • Page 4

    AD8123 Parameter POWER SUPPLY Operating Voltage Range Positive Quiescent Supply Current Negative Quiescent Supply Current Supply Current Drift Positive Power Supply Rejection Ratio Negative Power Supply Rejection Ratio Power Down, V (Minimum) IH Power Down, V ...

  • Page 5

    ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltage Power Dissipation Input Voltage (Any Input) Storage Temperature Range Operating Temperature Range Lead Temperature (Soldering, 10 sec) Junction Temperature Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to ...

  • Page 6

    AD8123 PIN CONFIGURATION AND FUNCTION DESCRIPTION Table 4. Pin Function Descriptions Pin No. Mnemonic 1, 10, 20, 21, 30 +IN CMP1 3 −IN CMP1 4 OUT CMP1 5 V _CMP S+ 6 OUT CMP2 7 −IN CMP2 ...

  • Page 7

    TYPICAL PERFORMANCE CHARACTERISTICS T = 25° ± 150 Ω, Belden Cable (BL-7987R Figure 17, unless otherwise noted GAIN POLE p-p ...

  • Page 8

    AD8123 1.5 50m 150m 300m 1.0 0.5 0 –0.5 –1.0 –1 100 150 200 250 300 TIME (ns) Figure 11. Pulse Response for Various Cable Lengths (2 MHz) 10000 0m 150m 300m 1000 100 10 100k 1M 10M ...

  • Page 9

    V PEAK V POLE 1.8 V GAIN 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0 100 125 150 175 200 225 CABLE LENGTH (meters) Figure 17. Recommended Settings for UTP Cable 2 1.8 ...

  • Page 10

    AD8123 THEORY OF OPERATION The AD8123 is a unity-gain, triple, wideband, low noise analog line equalizer that compensates for losses in UTP and coaxial cables up to 300 meters in length. The 3-channel architecture is targeted at high resolution RGB ...

  • Page 11

    APPLICATIONS INFORMATION BASIC OPERATION The AD8123 is easy to apply because it contains everything on-chip needed for cable loss compensation. Figure 20 shows a basic application circuit (power supplies not shown) with common-mode sync pulse extraction that is compatible with ...

  • Page 12

    AD8123 SYNC PULSE EXTRACTION USING COMPARATORS The AD8123 is useful in many systems that transport computer video signals, which are typically comprised of red, green, and blue (RGB) video signals and separate horizontal and vertical sync signals. Because the sync ...

  • Page 13

    USING THE AD8123 WITH COAXIAL CABLE The V control allows the AD8123 to be used with other POLE types of cable, including coaxial cable. Figure 18 presents the recommended settings for and V PEAK POLE AD8123 ...

  • Page 14

    AD8123 POWER SUPPLY FILTERING External power supply filtering between the system power supplies and the AD8123 is required in most applications to prevent supply noise from contaminating the received signal as well as to prevent unwanted feedback through the supplies ...

  • Page 15

    INPUT COMMON-MODE RANGE Most applications that use the AD8123 as a receiver use a driver (such as one from the AD8146/AD8147/AD8148 AD8133, or the AD8134) powered from ±5 V supplies. This places the common-mode voltage on the line nominally at ...

  • Page 16

    ... Temperature Range 1 AD8123ACPZ −40°C to +85°C 1 AD8123ACPZ-R7 −40°C to +85°C 1 AD8123ACPZ-RL −40°C to +85° RoHS Compliant Part. ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 6.00 BSC SQ 0.60 MAX ...