LMX2487 - National Semiconductor

LMX2487 High Performance Delta-Sigma Low Power Dual PLLatinum Frequency Synthesizers

The LMX2487 is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. It is fabricated using National Semiconductor’s advanced process. With delta-sigma architecture, fractional spurs at lower offset frequencies are pushed to higher frequencies outside the loop bandwidth. The ability to push close in spur and phase noise .

Features

Quadruple Modulus Prescalers for Lower Divide Ratios n RF PLL: 16/17/20/21 or 32/33/36/37 n IF PLL: 8/9 or 16/17 Advanced Delta Sigma Fractional Compensation n 12 bit or 22 bit selectable fractional modulus n Up to 4th order programmable delta-sigma modulator Features for Improved Lock Times and Programming n Fastlock / Cycle slip reduction n Integrated time-out counter n Single word write to change frequencies with Fastlock Wide Operating Range n LMX2487 RF PLL: 3.0 GHz to 6.0 GHz Useful Features n Digital lock detect output n Hardware and software power-down control n On-chip crystal referen.