ADRF6750

950 MHz to 1575 MHz Quadrature Modulator with Integrated Fractional-N PLL and VCO ADRF6750 FEATURES I/Q modulator with integrated fractional-N PLL and VCO Gain control span: 47 dB in 1 dB steps Output frequency range: 950 MHz to 1575 MHz Output 1 dB compression: 8.5 dBm Output IP3: 23 dBm Noise floor: −162 dBm/Hz Baseband modulation bandwidth: 250 MHz (1 dB) Output frequency resolution: 1 Hz Functions with external VCO for extended frequency range SPI and I2C-compatible serial interfaces Power supply: 5 V/310 mA GENERAL DESCRIPTION The ADRF6750 is a highly integrated quadrature modulator, frequency synthesizer, and programmable attenuator. The device covers an operating frequency range from 950 MHz to 1575 MHz for use in satellite, cellular and broadband communications. The ADRF6750 modulator includes a high modulus fractional-N frequency synthesizer with integrated VCO, providing better than 1 Hz frequency resolution, and a 47 dB digitally controlled output attenuator with 1 dB steps. Control of all the on-chip registers is through a user-selected SPI interface or I2C interface. The device operates from a single power supply ranging from 4.75 V to 5.25 V. FUNCTIONAL BLOCK DIAGRAM VCC1 3.3V REGULATOR VCC2 VCC3 VCC4 REGOUT VREG1 VREG2 VREG3 VREG4 VREG5 VREG6 LOMONP LOMONN RFOUT TXDIS IBBP IBBN CCOMP1 CCOMP2 CCOMP3 47dB GAIN CONTROL RANGE 0°/90° OUTPUT STAGE VCO CORE VTUNE TESTLO TESTLO QBBP QBBN RSET REFERENCE REFIN REFIN ×2 DOUBLER 5-BIT DIVIDER ÷2 + PHASE FREQ...