A 5.5 GHz fractional frequency-synthesizer IC

Abstract

We report a GaAs-AlGaAs fractional frequency-synthesizer IC with a 5.5 GHz feedback divider, 2 GHz reference divider, 500 MHz phase-frequency detector, 1 ns charge-pump pulses, gain-normalized output current, and 18 pA/sub rms///spl radic/Hz in-band phase noise. The feedback divider allows continuously selectable divide ratios from 12 to 16383, and supports dual-modulus pulse-swallowing fractional synthesis with single-bit control. The reference divider allows continuously selectable divide ratios from 1 to 4095; an optional divide-by-four/five input prescaler extends the divide ratios to 20475. The chip consumes 1 W from +5 V and -5.2 V supplies.