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Clocking chips simplify system design with low additive jitter

Santa Clara, Calif. — National Semiconductor Corp. has introduced a family of three ultra-low-noise and fully-featured clock buffers, dividers and distributors that simplify system clock design while claiming the industry's lowest additive noise. The LMK01000, LMK01010 and LMK01020 devices divide and distribute low-jitter clocks throughout high-performance systems such as wireless infrastructure, test and measurement, and medical ultrasound and imaging.

The LMK01000, LMK01010 and LMK01020 ultra low-noise clock buffers, dividers and distributors provide 1.6 GHz operation with low additive RMS jitter of 30 femtoseconds (fs). Each individual clock output features an independently programmable divider and skew control circuit. These features allow the distribution of eight unique frequencies at eight unique skew relationships. The output of the dividers can be synchronized by an external pin.

The PowerWise LMK010x0 family is available in three output configurations. The LMK01000 offers a mix of three low-voltage differential signaling (LVDS) and five low-voltage positive-emitter-coupled logic (LVPECL) outputs; the LMK01010 is offered with eight LVDS outputs to address low-power applications; and the LMK01020 provides eight LVPECL outputs to support ultra-high-performance applications.

All three products provide energy-efficient power-noise specifications. The LMK01000 offers 8.9 mW-ps per channel, while the LMK01010 is rated at 5.3 mW-ps per channel and the LMK01020 at 11.2 mW-ps per channel.

The devices' low additive jitter allows system designers to distribute multiple copies of a clean clock (while maintaining clock integrity) and eliminates the need for additional jitter cleaning components, said National. Each device's output offers a programmable skew control circuit that simplifies board layout, enabling the designer to adjust the skew of each clock output and compensate for board trace mismatch.

Available in 48-pin LLP packages, the LMK01000, LMK01010 and LMK01020 ultra-low-noise clock buffers, dividers and distributors are pin and footprint compatible with National's LMK02000 and LMK03000 family of precision clock conditioners.

Pricing: $7.25 each in quantities of 1,000.
Availability: Available now.
Product information:
LMK01000, LMK01010, LMK01020, interface products, and clock design tool

National Semiconductor , www.national.com

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