Triple Differential Receiver with Adjustable Line Equalization Data Sheet AD8123 FEATURES FUNCTIONAL BLOCK DIAGRAM V V V V PEAK POLE OFFSET GAIN Compensates cables to 300 meters for wideband video Fast rise and fall times AD8123 4.9 ns with 2 V step at 150 meters of UTP cable 8.0 ns with 2 V step at 300 meters of UTP cable IN R OUT R 55 dB peak gain at 100 MHz +IN R Two frequency response gain adjustment pins IN High frequency peaking adjustment (V ) PEAK G OUT G Broadband flat gain adjustment (V ) GAIN +IN G Pole location adjustment pin (V ) POLE IN B Compensates for variations between cables OUT B +IN Can be optimized for either UTP or coaxial cable B DC output offset adjust (V ) OFFSET IN CMP1 Low output offset voltage: 24 mV OUT CMP1 +IN CMP1 Compensates both RGB and YPbPr IN Two on-chip comparators with hysteresis CMP2 OUT CMP2 Can be used for common-mode sync extraction +IN CMP2 Available in 40-lead, 6 mm 6 mm LFCSP Figure 1. APPLICATIONS Keyboard-video-mouse (KVM) Digital signage RGB video over UTP cables Professional video projection and distribution HD video Security video For added flexibility, an optional pole adjustment pin, VPOLE, GENERAL DESCRIPTION allows movement of the pole locations, allowing for the The AD8123 is a triple, high speed, differential receiver and compensation of different gauges and types of cable as well equalizer that compensates for the transmission losses of UTP as variations between different cables and/or equalizers. The and coaxial cables up to 300 meters in length. Various gain VOFFSET pin allows the dc voltage at the output to be adjusted, stages are summed together to best approximate the inverse adding flexibility for dc-coupled systems. frequency response of the cable. Logic circuitry inside the AD8123 controls the gain functions of the individual stages so that the The AD8123 is available in a 6 mm 6 mm, 40-lead LFCSP lowest noise can be achieved at short-to-medium cable lengths. and is rated to operate over the extended temperature range of This technique optimizes its performance for low noise, short- 40C to +85C. to-medium range applications, while at the same time provides UXGA RESOLUTION IMAGE UXGA RESOLUTION IMAGE AFTER 300 METER CAT-5 CABLE AFTER 300 METER CAT-5 CABLE the high gain bandwidth required for long cable equalization BEFORE AD8123. AFTER AD8123. (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 PEAK pin controls the amount of high frequency Figure 2. UXGA Resolution Images Before and After the AD8123 peaking and the VGAIN pin adjusts the broadband flat gain, which compensates for the low frequency flat cable loss. Rev. B Document Feedback 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20072016 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 06814-001 06814-019AD8123 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Comparators ............................................................................... 11 Applications ....................................................................................... 1 Sync Pulse Extraction Using Comparators ............................. 12 Functional Block Diagram .............................................................. 1 Using the VPEAK, VPOLE, VGAIN, and VOFFSET Inputs ................... 12 General Description ......................................................................... 1 Using the AD8123 with Coaxial Cable .................................... 13 Revision History ............................................................................... 2 Driving 75 Video Cable With the AD8123 ........................ 13 Specif icat ions ..................................................................................... 3 Driving a Capacitive Load ......................................................... 13 Absolute Maximum Ratings ............................................................ 5 Filtering the RGB Outputs ........................................................ 13 Thermal Resistance ...................................................................... 5 Power Supply Filtering ............................................................... 14 ESD Caution .................................................................................. 5 Layout and Power Supply Decoupling Considerations ......... 14 Pin Configuration and Function Descriptions ............................. 6 Input Common-Mode Range ................................................... 15 Typical Performance Characteristics ............................................. 7 Small Signal Frequency Response ............................................ 15 Theory of Operation ...................................................................... 10 Power-Down ............................................................................... 15 Input Common-Mode Voltage Range Considerations ......... 10 Outline Dimensions ....................................................................... 16 Applications Information .............................................................. 11 Ordering Guide .......................................................................... 16 Basic Operation .......................................................................... 11 REVISION HISTORY 1/16 Rev. A to Rev. B Added Figure 2 Caption................................................................... 1 Changes to Figure 4 and Table 4 ..................................................... 6 Updated Outline Dimensions ....................................................... 16 Changes to Ordering Guide .......................................................... 16 11/07Rev. 0 to Rev. A Changes to Features .......................................................................... 1 Changes to Ordering Guide .......................................................... 16 8/07Revision 0: Initial Version Rev. B Page 2 of 16