ADRF6801

Data Sheet 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO ADRF6801 FEATURES IQ demodulator with integrated fractional-N PLL LO frequency range: 750 MHz to 1150 MHz Input P1dB: 12.5 dBm Input IP3: 25 dBm Noise figure (DSB): 14.3 dB Voltage conversion gain: 5.1 dB Quadrature demodulation accuracy Phase accuracy: 0.3° Amplitude accuracy: 0.05 dB Baseband demodulation: 275 MHz, 3 dB bandwidth SPI serial interface for PLL programming 40-lead, 6 mm × 6 mm LFCSP APPLICATIONS QAM/QPSK RF/IF demodulators Cellular W-CDMA/CDMA/CDMA2000 Microwave point-to-(multi)point radios Broadband wireless and WiMAX GENERAL DESCRIPTION The ADRF6801 is a high dynamic range IQ demodulator with integrated PLL and VCO. The fractional-N PLL/synthesizer generates a frequency in the range of 3.0 GHz to 4.6 GHz. A divide-by-4 quadrature divider divides the output frequency of the VCO down to the required local oscillator (LO) frequency to drive the mixers in quadrature. Additionally, an output buffer can be enabled that generates an fVCO/2 signal for external use. The PLL reference input is supported from 10 MHz to 160 MHz. The phase detector output controls a charge pump whose output is integrated in an off-chip loop filter. The loop filter output is then applied to an integrated VCO. The IQ demodulator mixes the differential RF input with the complex LO derived from the quadrature divider. The differential I and Q output paths have excellent quadrature accuracy and can handle b...