Summary of SINGLE-ENDED VIDEO/DIGITAL INPUT TO DIFFERENTIAL OUTPUT DRIVER (HIGH SPEED DIFFERENTIAL DRIVER)
This project is a low-cost AD8131-based board that converts single-ended video or digital signals to differential outputs for transmission up to 300 meters over twisted pair (Cat3/Cat5) or coax. It uses the AD8131 fixed-gain-2 differential driver, requires +/-5V supplies, includes RCA input, screw-terminal differential output, on-board termination resistors, and a power LED. The design minimizes attenuation, ensures low balance error and low distortion, and suits high-speed analog or digital signal transmission.
Parts used in the AD8131 Twisted-Pair Video/Digital Transmitter:
- AD8131 differential driver IC
- RCA connector (J1) for single-ended input
- Screw terminal connector (CN2) for twisted pair output
- Resistor R7 (line termination)
- Resistor R8 (line termination)
- Power LED (D1)
- Dual 5V supply connection (+5V and -5V)
- PCB (36.67 x 24.77 mm)
- Supporting passive components as placed on PCB (as described in article)
The project described here is a low-cost solution to transmit a video or digital signal up to 300 Meters over a twisted pair cable. The project has been designed using the AD8131 chip which is a differential driver for the transmission of high-speed signals over low-cost twisted pair or coaxes cables. The project can be used for either analog or digital video signals or for other high-speed data transmissions. It is capable of driving either Cat3 or Cat5 twisted pair or coax with minimal line attenuation. The AD8131 has on-chip resistors that provide for a gain of 2 without any external parts. Several on-chip resistors are trimmed to ensure that the gain is accurate, the common-mode rejection is good, and the output is well balanced. This makes the AD8131 very suitable as a single-ended-to-differential twisted-pair line driver. The board works with +/-5V DC (Dual 5V) supply, RCA connector J1 to feed single-ended Video or digital signal, connector CN2 is used to connect the twisted pair cable (CAT5), D1 Power LED, Resistor R7 and R8 terminate the line at transmitting side.
The AD8131 is a differential or single-ended input to differential output driver requiring no external components for a fixed gain of 2. The AD8131 is a major advancement over op amps for driving signals over long lines or for driving differential input ADCs. The AD8131 has a unique internal feedback feature that provides output gain and phase matching that are balanced to −60 dB at 10 MHz, reducing radiated EMI and suppressing harmonics. Manufactured on the Analog Devices, Inc. next-generation XFCB bipolar process, the AD8131 has a −3 dB bandwidth of 400 MHz and delivers a differential signal with very low harmonic distortion.
FEATURES
- Supply +/-5V DC
- Fixed Gain 2
- Single-Ended Video or Digital Signal Input – RCA Connector
- Differential Output – Screw Terminal
- Low Balance Error
- Output Impedance 100 Ohms
- PCB Dimensions 36.67 x 24.77 mm
Read more: SINGLE-ENDED VIDEO/DIGITAL INPUT TO DIFFERENTIAL OUTPUT DRIVER (HIGH SPEED DIFFERENTIAL DRIVER)
- What is the maximum transmission distance for this project?
The project is designed to transmit video or digital signals up to 300 Meters over a twisted pair cable. - Which IC is used to drive the twisted pair lines?
The AD8131 differential driver IC is used. - What supply voltages does the board require?
The board works with a +/-5V DC (Dual 5V) supply. - What type of input connector is used for single-ended video or digital signals?
An RCA connector (J1) is used for the single-ended input. - What connector is used to attach the twisted pair cable?
Connector CN2 (screw terminal) is used to connect the twisted pair cable such as CAT5. - Does the AD8131 require external parts to set its gain?
No, the AD8131 has on-chip resistors that provide a fixed gain of 2 without external parts. - Can this board drive Cat3 and Cat5 cables?
Yes, it is capable of driving either Cat3 or Cat5 twisted pair or coax with minimal line attenuation. - Are line termination components included on the transmitting side?
Yes, resistor R7 and R8 terminate the line at the transmitting side. - What is the PCB size for this project?
The PCB dimensions are 36.67 x 24.77 mm. - What bandwidth does the AD8131 provide?
The AD8131 has a -3 dB bandwidth of 400 MHz as stated in the article.
