Programmable skew components offer designers migration from 3.3V to 2.5V, no board redesign

Fremont, CA, March 1, 2004 – Exar Corporation, a provider of high-performance, mixed-signal silicon solutions for the worldwide communications infrastructure today, expanded its market-proven communications portfolio by entering the market for clock distribution devices. The Company unveiled a family of five new programmable skew clock components ” including an industry first: smallest package (32-pin) and the highest frequency range (200MHz) of any 3.3V or 2.5V devices.

Whether regulating data transmissions or executing system instructions, clocks perform the critical role of producing precisely timed and repeated impulses that synchronize the overall system or other embedded applications. Driving the need for better performing clocks are faster processors, faster memory and increasingly lower voltage requirements, especially in new designs. Keeping pace with these trends has put new demands on clocks for lower jitter, better skew specifications and unprecedented device reliability. Leveraging a rich history of analog and Phase Lock Loop (PLL) design expertise on a growing market opportunity, Exar has developed a series of innovative new clock and timing devices targeting wireless base stations, network switches and routers, among others.

In addition to the other four new programmable skew clocks, Exar has developed an industry-first with the XRK4999. Three elements distinguish the component from competitive offerings: a 32-pin package for either 3.3V or 2.5V, a redundant input clock and the widest frequency range (3.75 to 200MHz) with a four bank skew and 250 pico second accuracy. Exar is the only company to offer these in a single solution, which is critical in designing highly integrated, small form factor components for leading edge Networking and Transmission applications.

Designers no longer have to contend with layout and/or clock tree redesigns to support industry-changing system voltage requirements. Customers do not have to carry two programmable skew clock inventories (single Bill-of-Materials [BOM]) for 3.3 or 2.5Volt applications. Exar's new devices eliminate these challenges. The XRK499x series (3.3V or 2.5V) clocks are offered in a small form factor (low-pin count), and standard pin-outs – this is in direct contrast to conventional devices that lack an easy (same form factor) migration path from 3.3Vto 2.5V. Designers are assured a seamless migration from 3.3V to 2.5V, and OEM customers can get their products to market faster than the competition.

The XRK499x portfolio of 3.3/2.5 Volt programmable skew clocks consists of five different products offering designers numerous options including different package sizes, faster speeds (output frequency of up to 200 MHz), plus better jitter and skew performance. Each product incorporates four pairs of programmable skew and zero propagation delay outputs that provide timing delays optimizing high-performance clock distribution circuits. The clock's skew control is guaranteed to be as low as 250 pico seconds, with selectable skew between outputs from 750 pico seconds to 18 nanoseconds. Also, all devices in the series have flexible output functions (divide-by-two, or four) which, when combined with the internal PLL, enable transmission of low-frequency clock impulses that can then be multiplied by a factor of two or four at the clock's destination. This flexibility means designers now have more options than before, and no longer have to contend with static, or fixed outputs.

The XRK4991 and XRK4991A are in 32-pin packages and have a frequency range of 3.75 to 100MHz with four bank skew, and are available with 250/500/750 pico second accuracy. In addition, the XRK4911 has a frequency range of 3.75 to 200MHz with 250 pico seconds accuracy. The XRK4993 is offered in a 28-pin package, and it has a frequency range of 3.75 to 100MHz with three bank skew and is available with 250/500/750 pico second accuracy.

In 1,000 piece quantities, for commercial temperatures the XRK4991/91A/93CJ-2 (250 pico second accuracy) are $8.71, XRK4991/91A/93CJ-5 (500 pico second accuracy) is $6.71 and XRK4991/91A/93CJ-7 (750 pico second accuracy) is $5.15. The XRK49911 in 1,000 piece quantities (commercial temperatures) are $10.46 (250 pico second accuracy), $8.05 (500 pico second accuracy), and $6.18 (750 pico second accuracy). The XRK4999 is $11.94 in 1,000 piece quantities. The parts are also available in the industrial temperature, at 1,000 piece pricing the XRK4991/91A/93IJ-5 (500 pico second accuracy) are $7.38, and $5.67 for the RK4991A/93IJ-7 (750 pico second accuracy). Samples of all these products are available now.

For more information about Exar visit

XRK4999 data sheet
(you will have to provide some contact info to get the data sheet but I was able to get it after providing simple contact info.

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