Moteur de recherche de fiches techniques de composants électroniques |
|
AD8123ACPZ Fiches technique(PDF) 10 Page - Analog Devices |
|
AD8123ACPZ Fiches technique(HTML) 10 Page - Analog Devices |
10 / 16 page AD8123 Rev. A | Page 10 of 16 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 applications but can be used in HD YPbPr applications as well. Three continuously adjustable control voltages, common to the RGB channels, are available to the designer to provide compensation for various cable lengths as well as for variations in the cable itself. The VPEAK input is used to control the amount of high frequency peaking. VPEAK is the primary control that is used to compensate for frequency and cable-length dependent, high frequency losses that are present due to the skin effect of the cable. A second control pin, VGAIN, is used to adjust broadband gain to compensate for low frequency flat losses present in the cable. A third control, VPOLE, is used to move the positions of the equalizer poles and can be linearly derived from VPEAK, as illustrated in the Typical Performance Characteristics and Applications Information sections, for UTP and coaxial cables. Finally, an output offset adjust control, VOFFSET, allows the designer to shift the output dc level. The AD8123 has a high impedance differential input that makes termination simple and allows dc-coupled signals to be received directly from the cable. The AD8123 input can also be used in a single-ended fashion in coaxial cable applications. For differential systems that require very high CMRR, a triple differential receiver, such as the AD8143 or AD8145, can be placed in front of the AD8123. The AD8123 has a low impedance output that is capable of driving a 150 Ω load. For systems where the AD8123 has to drive a high impedance capacitive load, it is recommended that a small series resistor be placed between the output and load to buffer the capacitance. The resistor should not be so large as to reduce the overall bandwidth to an unacceptable level. The AD8123 is designed such that systems that use short-to- medium-length cables do not pay a noise penalty for excess gain that they do not require. The high gain is only available for longer length systems where it is required. This feature is built into the VPEAK control and is transparent to the user. Two comparators are provided on-chip that can be used for sync pulse extraction in systems that use sync-on-common mode encoding. Each comparator has very low output impedance and can therefore be used in a source-only cable termination scheme by placing a series resistor equal to the cable characteristic impedance directly on the comparator output. Additional details are provided in the Applications Information section. INPUT COMMON-MODE VOLTAGE RANGE CONSIDERATIONS When using the AD8123 as a receiver, it is important to ensure that its input common-mode voltage stays within the specified range. The received common-mode level is calculated by adding the common-mode level of the driver, the single-ended peak amplitude of the received signal, the amplitude of any sync pulses, and the other induced common-mode signals, such as ground shifts between the driver and the AD8123 and pickup from external sources, such as power lines and fluorescent lights. See the Applications Information section for more details. |
Numéro de pièce similaire - AD8123ACPZ |
|
Description similaire - AD8123ACPZ |
|
|
Lien URL |
Politique de confidentialité |
ALLDATASHEET.FR |
ALLDATASHEET vous a-t-il été utile ? [ DONATE ] |
À propos de Alldatasheet | Publicité | Contactez-nous | Politique de confidentialité | Echange de liens | Fabricants All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |