A sub-mA FH frequency synthesizer technique

A novel frequency-hopping spread-spectrum transmitter architecture is presented that provides robust communications in the 915 MHz ISM band while dissipating very low power. The frequency-hopping front-end consists of a VCO, dividers and output stage. A base-band predistortion algorithm allows hopping with minimum hardware complexity. The TX front-end has been fabricated in silicon-on-anything (SOA) bipolar technology and a BFSK modulated wireless link using a dedicated receiver has been realized. A 1kbps, 1khop/s link with a BER smaller than 1.1 % has been achieved at -25 dBm output power while having 64 orthogonal channels. The synthesizer architecture (VCO+divider+base-band) dissipates only 870mA