Part # LMX2470 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LMX2470 2.6 GHz Delta-Sigma Fractional-N PLL with 800 MHz Integer-N P


Part Details:

LMX2470 April 2003 LMX2470 2.6 2.6 GHz Delta-Sigma Fractional-N PLL with 800 MHz GHz Integer-N PLLGeneral Description Features Delta-Sigma The LMX2470 is a low power, high performance delta-sigma n Low in-band phase noise and low fractional spurs fractional-N PLL with an auxiliary integer-N PLL. The device n 12 bit or 22 bit selectable fractional modulus is fabricated using National Semiconductor s advanced BiC- n Up to 4th order programmable delta-sigma modulator MOS process. n Enhanced Anti-Cycle Slip Fastlock Circuitry With delta-sigma architecture, fractional spur compensation Fastlock is achieved with noise shaping capability of the delta-sigma Cycle slip reduction modulator and the inherent low pass filtering of the PLL loop Integrated timeout counters filter. Fractional spurs at lower frequencies are pushed to Fractional-N n Digital lock detect output higher frequencies outside the loop bandwidth. Unlike ana- n Prescalers allow wide range of N values log compensation, the digital feedback techniques used in RF PLL: 16/17/20/21 the LMX2470 are highly resistant to changes in temperature IF PLL: 8/9 or 16/17 and variations in wafer processing. With delta-sigma archi- n Crystal Reference Frequency up to 110 MHz tecture, the ability to push close in spur and phase noise n On-chip crystal reference frequency doubler. energy to higher frequencies is a direct function of the modu-lator order. The higher the order, the more this energy can be n Phase Comparison Frequency up to 30 MHz spread to higher frequencies. The LMX2470 has a program- n Hardware and software power-down control mable modulator up to order four, which allows the designer n Ultra low consumption: I = 4.1 mA (typical) PLL CC to select the optimum modulator order to fit the phase noise,spur, and lock time requirements of the system. Applications Programming is fast and simple. Serial data is transferred with n Cellular Phones and Base Stations into the LMX2470 via a three line MICROWIRE interface CDMA, WCDMA, GSM/GPRS, TDMA, EDGE, PDC (Data, Clock, Load Enable). Nominal supply voltage is 2.5 V. n Applications requiring fine frequency resolution The LMX2470 features a typical current consumption of 4.1


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LMX2470.pdf Datasheet