National Semiconductor Corp. has launched a family of three ultra low-noise and fully-featured clock buffers, dividers and distributors that simplify system clock design while providing the industry’s lowest additive noise – 30 fs of additive RMS jitter. The high-performance LMK01000, LMK01010 and LMK01020 divide and distribute low-jitter clocks throughout high-performance systems such as wireless infrastructure, test and measurement, and medical ultrasound and imaging.

Article Tools

• 

The LMK010x0 family offers three output configurations: The LMK01000 has 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 has eight LVPECL outputs to support ultra high-performance applications. National said that all three products provide power-noise specifications that place them among its PowerWise family of energy-efficient products. 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. 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, said National.

The LMK01000, LMK01010 and LMK01020 ultra low-noise clock buffers, dividers and distributors are pin and footprint compatible with LMK02000 and LMK03000 family of precision clock conditioners. They join the recently released LMK03000D and LMK03001D low jitter (1.2 ps RMS) precision clock conditioners aimed at high-performance applications.

Implemented in proprietary BiCMOS8 process technology, the LMK01000, LMK01010 and LMK01020 provide 1.6 GHz operation with low additive RMS jitter of 30 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 LMK010x0 family of devices has two separate clock inputs with a user programmable mux for selection between two different clock domains. These devices come in 48-pin LLP packages.

Available now, the LMK01000, LMK01010 and LMK01020 are priced at $7.25 each in 1,000-unit quantities.

www.national.com