Highly Integrated Single-Chip Sub 1 GHz RF Transceiver

A highly integrated single-chip transceiver solution, the OL2381 is ideally suited to telemetry applications operating in the ISM/SRD bands. The small form factor, low power consumption and wide supply voltage range make this device suitable for use in battery powered, handheld devices and their counter parts.

The device utilizes a fully integrated, programmable fractional-N PLL (including loop filter) to control the Local Oscillator (LO), thus supporting multi-channel operation and frequency hopping schemes. This feature also allows programmable frequency steps for crystal (XTAL) drift compensation.

The device can employ ASK, FSK or GFSK type modulation. The ASK modulation characteristics are fully programmable by varying the power amplifier output power in accordance with the TX data. The FSK modulation utilizes the fractional-N PLL capability to precisely modulate the LO frequency with the TX data (in loop modulation). Relaxed narrow band applications can utilize an on-chip GFSK type modulation to improve the spectral occupancy.

The device is based on a low IF direct conversion receiver architecture, with on-chip IF filtering and programmable channel bandwidth. After filtering and amplification the quadrature signals are digitized, demodulated and processed in the digital domain.

Baseband processing of the received signal comprises a demodulator, a data-slicer and clock recovery followed by a Manchester decoder. Automated signal signature recognition units are available to allow simple, fast and reliable data reception.

The device is controlled via a three-wire serial interface (SPI) with data input and output, data clock and interface enable. The interface can be configured to a full SPI interface with separate data and clock pins. Additional pins are available to access internal signals in real-time.