The AS3977 is a low-power fully integrated ETSI, FCC and ARIB compliant FSK/ASK transmitter capable of operating at any ISM frequency in the range of 300 to 1000 MHz. It is based on a sigma-delta controlled fractional-N synthesiser phase locked loop (PLL) with fully integrated voltage controlled oscillator (VCO). The power amplifier (PA) output is programmable and can deliver power ranging from 20dBm up to +8dBm. An on-chip low drop-out (LDO) regulator is available in case an accurate output power independent of voltage supply variation is required.