AT48802

Features:

· Two Independent PN (Pseudo-Random Noise) Generators
· Programmable R7 (128) to R13 (8,192) PN Sequence Lengths
· Programmable Tau-Dither Amplitude
· Programmable PN Phase Adjustment to 1/16 Chip
· Correlation Acquisition Interface
· Programming Register Control
· Microcontroller Compatible Bus Interface
· Patent-Pending Frequency Diversity
· Low Speed Link Data Path for Supervisory and Setup Functions


Pinout




Specifications

Lead Temperature ...........................................300°C
Storage Temperature...................... -55°C to +125°C
V_CC, Supply Voltage .......................... -0.3V to +7.0V
Input Pin Voltage........................-0.3V to VCC + 0.3V
Input Pin Current.......................... -10 mA to +10 mA

*NOTICE: Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.


Description

The AT48802 Spread-Spectrum Signal Processor (SSSP) chip from Atmel handles all PN code generation, synchronization, and handshaking required for either station (handset or base station) of a time division duplex direct sequence spread-spectrum cordless telephone. The AT48802 supports RF spreading and despreading for the best rejection of interference. In conjunction with a single-chip microcontroller, the circuit performs the following functions:
· Generates a pseudo-random sequence for spreading the transmitted signal.
· Generates a pseudo-random sequence for despreading in the receiver.
· Generates a sliding phase PN for acquiring synchronization with an incoming signal.
· Controls receive signal strength measurement timing for correlation peak detection.
· Operates a tau-dither tracking loop, with adaptive threshold, to maintain synchronization with the incoming signal.
· Controls transmit keying antenna switching for time-division duplexing.
· Controls receive audio or data sampling time and duration.
· Controls wake-up and sleep functionality for remote battery operated handset.

The AT48802 unique spread-spectrum architecture capitalizes on the benefits of long range, signal-to-noise improvements, multi-path protection, and privacy. This design employs proven analog FM modulation to achieve the lowest possible system cost yet the highest processing gain and sound quality. The chip is a fully static design.