ADF4251

www.DataSheet4U.com Dual Fractional-N/Integer-N Frequency Synthesizer ADF4251 FEATURES 3.0 GHz Fractional-N/1.2 GHz Integer-N 2.7 V to 3.3 V Power Supply Separate V P Allows Extended Tuning Voltage to 5 V Programmable Dual Modulus Prescaler RF: 4/5, 8/9 IF: 8/9, 16/17, 32/33, 64/65 Programmable Charge Pump Currents 3-Wire Serial Interface Digital Lock Detect Power-Down Mode Programmable Modulus on Fractional-N Synthesizer Trade-Off Noise versus Spurious Performance Software and Hardware Power-Down APPLICATIONS Base Stations for Mobile Radio (GSM, PCS, DCS, CDMA, WCDMA) Wireless Handsets (GSM, PCS, DCS, CDMA, WCDMA, PHS) Wireless LANs Communications Test Equipment CATV Equipment GENERAL DESCRIPTION The ADF4251 is a dual fractional-N/integer-N frequency synthesizer that can be used to implement local oscillators (LO) in the upconversion and downconversion sections of wireless receivers and transmitters. Both the RF and IF synthesizers consist of a low noise digital PFD (phase frequency detector), a precision charge pump, and a programmable reference divider. The RF synthesizer has a ⌺-⌬ based fractional interpolator that allows programmable fractional-N division. The IF synthesizer has programmable integer-N counters. A complete PLL (phase-locked loop) can be implemented if the synthesizer is used with an external loop filter and VCO (voltage controlled oscillator). Control of all the on-chip registers is via a simple 3-wire interface. The devices operate with a power supply ...