A 5.9-to-7.8 GHz VCO in 65 nm CMOS using high-Q inductor in an embedded Wafer Level BGA package

We present a 5.9-to-7.8 GHz voltage-controlled oscillator (VCO) fabricated in a 65 nm CMOS technology and assembled in a chip-scale embedded Wafer Level Ball-Grid-Array (eWLB) package. The VCO uses a high-quality LC-tank inductor, realized in the fan-out area of the package. This inductor achieves a quality factor of 28 at a frequency of 6.5 GHz. Using this high-Q inductor it was possible to reduce the phase noise by as much as 9 dB at a carrier offset of 1 MHz compared to a reference VCO, which is identical to the first one, but uses an integrated on-chip inductor instead. The VCO using the embedded eWLB inductor offers a phase noise of -118.3 dBc/Hz at 1 MHz and achieves an output power of -1.1 dBm. The VCO core consumes 20.2 mA from a 1.2 V supply. The presented results demonstrate an excellent potential for embedded inductors in the fan-out area of an eWLB package for circuits requiring high-Q inductors.