General Description
The AS3977 is a low-power fully integrated ETSI, FCC and ARIB compliant FSK transmitter capable of operating at any ISM frequency in the range of 300 to 928 MHz. It is based on a sigma-delta controlled fractional-N synthesiser phase locked loop with fully integrated voltage controlled oscillator. The power amplifier output is programmable and can deliver output power ranging from –20dBm up to +10dBm. An on-chip low drop-out regulator is available in case an accurate output power independent of voltage supply variation is required

Main Characteristics
- 2.0 – 3.6V power supply
- Power down current consumption 100 nA (3V, 25oC)
- Output power up to +10dBm
- Occupied bandwidth 8.5 kHz (4.8 kb/s, FFSK, ARIB)
- Operating temperature range -40oC to +85oC

Additional Features
- Sigma-Delta controlled fractional-N synthesiser
- Resolution of synthesiser <100Hz
- Fully integrated PLL
- Fully integrated voltage controlled oscillator
- 4kV ESD protection (1.5kV for analogue pins)
- Automatic antenna tuning
- 12 – 20 MHz crystal oscillator
- On-chip temperature sensor with digital readout for AFC purposes
- Integrated Manchester coder
- Digital lock detector
- Low drop-out regulator
- Bi-directional serial interface