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.

The output signal can be shaped using a programmable Gaussian filter to minimise the occupied bandwidth and adjacent channel power. The maximum data rate can be up to 100 kb/s – depending on the required filtering.

The FSK frequency deviation is programmable up to a maximum of 64kHz.

The crystal oscillator can handle a wide range of frequencies. For narrow-band applications a temperature sensor with digital read-out is included that allows compensation of the crystal frequency drift due to temperature variation.

The AS3977 is connected to an external microcontroller via a bi-directional digital interface. The device operates at very low current consumption with a power supply range from 2.0V to 3.6V and can be powered down when not in use.

The device is fabricated in austriamicroystems advanced 0.35um SiGe-BiCMOS technology.