LTC6947

Features n LTC6947 Ultralow Noise 0.35GHz to 6GHz Fractional-N Synthesizer Description The LTC®6947 is a high performance, low noise, 6GHz phase-locked loop (PLL), including a reference divider, phase-frequency detector (PFD), ultralow noise charge pump, fractional feedback divider, and VCO output divider. The fractional divider uses an advanced, 4th order Δ∑ modulator which provides exceptionally low spurious levels. This allows wide loop bandwidths, producing extremely low integrated phase noise values. The programmable VCO output divider, with a range of 1 through 6, extends the output frequency range. The differential, low-noise output buffer has user-programmable output power ranging from –4.3dBm to +4.5dBm, and may be muted through either a digital input pin or software. The ultralow noise charge pump contains selectable high and low voltage clamps useful for VCO monitoring, and also may be set to provide a V+/2 bias. All device settings are controlled through a SPI-compatible serial port. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and FracNWizard is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Low Noise Fractional-N PLL n No ∆Σ Modulator Spurs n 18-Bit Fractional Denominator n 350MHz to 6GHz VCO Input Range n –226dBc/Hz Normalized In-Band Phase Noise Floor n –274dBc/Hz Normalized In-Band 1/f Noise n –157dBc/Hz Wideband Output Phase Noise Floor n Excellent Int...