20 mW SiGe-MMIC-VCO at 5 GHz with integrated 4:1 divider for use in a PLL

A 5 GHz SiGe MMIC-VCO with integrated 4:1 divider and an output power of more than 20 mW is presented. The VCO core has a differential topology with two buffered outputs. One output is connected to a 4:1 divider realized in ECL configuration and the other to an amplifier having 20 mW output power at 50 /spl Omega/. The 4:1 divider has a differential output and can be connected directly to a synthesizer IC with differential input to build up a PLL. The tuning range of the VCO is 700 MHz between a control voltage of 0 and 5 V. The variation of the output power is less than 1 dB over the whole tuning range. The total chip size is 800/spl times/400 /spl mu/m/sup 2/.