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