MINDSPEED announces the availability of the M21528, the industry’s first dual cable driver. This highly integrated IC enables an SMPTE-compatible SDI (serial digital interface) output signal at only one-third of the power consumption of existing solutions and half the required board space, not to mention the reduction in design complexity that it offers.

The SDI standard is commonly used in the video broadcast industry to connect individual components, and the interface was standardized by the Society of Motion Picture and Television Engineers (SMPTE). The standard defines how a digital video signal should be transmitted via a 75? coaxial cable, and it has three principal video signal variants: SD-SDI video, also known as standard definition video, HD-SDI video, or high definition video, and the most recent: 3G-SDI video. The 3G-SDI standard was introduced to enable the transport of video signals with a high resolution and high frame frequency. 3G-SDI is also referred to as full HD Video.

In addition to lesser components, an SDI video system consists of four core elements: cable equalizers (EQ), reclockers, cable drivers (CD) and crosspoint switches. Cable equalizers are needed to offset signal losses that occur when the video signal is transmitted via cables, while crosspoint switches are used to switch the signal from one input port to various output interfaces. CDR video reclockers are used to remove jitter from the signal before it is sent to the cable. And, finally, cable drivers amplify the signal and also form the output interface to the cable.

The cable driver is very critical to the system because all of its outputs are connected directly to the cable and it must fulfill all of the SMPTE’s requirements for the interface’s physical parameters. A compliant cable driver is only permitted to add a minimal amount of jitter to the signal, and it must have an 800mV single-ended output swing, while at the same time meeting the standard requirements for signal rise and fall time, and thus also the steepness of the signal edges, for all three video data rates. MINDSPEED’s M21528 is a cable driver that meets all of these requirements!

The M21528 exhibits very low power consumption and combines two cable drivers in a single package. It meets all specifications prescribed by the SMPTE and is thus suited to transfer digital video signals at all three data rates: 3G/HD/SD-SDI. The IC solution can drive 2 output signals onto 75? coax cables at data rates ranging from 143Mbits/s up to 2.97Gbits/s, and it delivers an output signal with a jitter of less than 20 picoseconds peak-to-peak at a data rate of 2.97Gbits/s. The M21528 dual cable driver is also equipped with a 2x2 input crosspoint switch and integrates the input and output terminations.

A clear trend toward larger systems with more SDI ports can be observed on the broadcast market. Frequently, however, larger systems simply can’t accommodate the growing number of required interfaces, leaving designers puzzling over how to fit more ports onto the same amount of available board space.

As a dual cable drive, the MINDSPEED M21528 is the ideal solution to fix the problem. Not only does the new IC help designers fit an SMPTE-compatible SDI port onto a fraction of the space needed by legacy systems, but it also creates additional space savings thanks to the integrated crosspoint switch, and integrated input and output terminations, which eliminates the need for adding these components externally.

In addition to the challenge of limited space, broadcast system designers are frequently confronted with the problem of high power dissipation and the related need for heat removal. At the same time, the current trend is toward CO2 and energy reduction, and this is driving the demand for systems that consume less energy. MINDSPEED´s dual cable driver is the first device of its kind to be manufactured using a deep sub-micron CMOS process, thus delivering previously unachievable energy savings. In fact, compared to competing solutions on the market, the M21528 consumes only one third of the power per channel!

Development of the first generation of 3G SDI-capable systems has shown that signal integrity needs to be more of a design focus than was the case with HD-SDI systems. For, in order to achieve full system performance for the higher data rates, many system developers were forced to change their designs by adding additional components to equalize the signal losses that were now distributed across the board. These additional external components in turn added system complexity and cost, while at the same time taking up precious board space. The M21528 helps designers reduce both complexity and cost, as it provides input equalization for an up to 40” strip of FR4 PCB, as well as two connectors.

In developing the M21528 cable driver IC, MINDSPEED set out to solve many of the problems faced by broadcast system designers – and definitely succeeded! MINDSPEED also offers related solutions, such as reclockers and cable equalizers, in addition to being a market leader for crosspoint switches.


Fig.1: Block Diagram of a Typical Video Routing Switcher
Fig.2: Functional Block Circuit Diagram of the M21528
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