Date: 19/10/2009

Triple-skew-compensating video delay line IC from ADI with analog and digital control

Precision analog semiconductor expert, Analog Devices has introduced the AD8120, a triple-skew-compensating video delay line IC for transmitting clear, sharp images long distances over twisted-pair cable for digital signage, KVM (keyboard, video, mouse), video projection and high-definition surveillance applications.

The AD8120 contains three delay paths that provide broadband delays up to 50 nanoseconds, in 0.8 ns increments, using 64 digital control steps or analog control adjustment. The delay technique used in the AD8120 minimizes noise and offset at the outputs, and the bandwidth ranges between 106 MHz and 152 MHz depending upon the delay setting. This high output bandwidth capability makes AD8120 ideal in applications that receive high-resolution video over UTP (unshielded twisted pair) cables.

The AD8120 compensates for the skew created by Cat5, Cat6 or Cat7 cables when transmitting analog video over long distance cables.

The other key features of the AD8120 IC include,

Better channel-to-channel matching: 30 mV offset matching RTI, 0.8% gain matching
No external circuitry required to correct for offsets
Independent red, green, and blue delay controls
Drives 4 double-terminated video loads

The logic circuitry inside the AD8120 provides for individual delay control of each path. The three delay times can be independently set using a standard four-wire SPI bus, standard I2C bus or by applying three analog control voltages to the VCR (voltage control red), VCG (voltage control green), and VCB (voltage control blue) pins. Analog control offers a simple solution for systems that do not have digital control available.

During video transmission in unshielded twisted pair cables the Skew, or arrival time mismatch, between video signals occurs due to the different twist rates used for each pair. For this reason, some pairs are longer than others, and in long cables, the difference in propagation time between two pairs can be well into the tens of nanoseconds, creating a noticeable degradation in video performance.

The suggested applications of the AD8120 IC include digital signage, RGB video over UTP cable, professional video projection and distribution, HD video, security video and general broadband delay lines.

Operating temperature range: -40°C to +85°C

Package: 5 mm × 5 mm 32-lead LFCSP package
Price: Each $14.75 for 1k pieces
Availability: Now in samples

For more details visit www.analog.com
Editorial Product Rating: Average Plus