原标题：Atmel AT86RF212低功耗ZigBee收发方案

　　Atmel 公司的AT86RF212是低功耗低电压700/800/900 MHz 收发器,特别设计用于IEEE Standard 802.15.4, ZigBee, 6LoWPAN以及高数据速率ISM应用. AT86RF212单片RF收发器提供了天线和微控制器间完整接口,包括有模拟无线电部分,包括时间和频率同步的数字调制和解调, 以及数据缓冲功能.接收灵敏度高达-110dBm,可编程TX输出功率高达+10dBm,工作电压从1.8V到3.6V,内部有电压稳压器和电池监视器,工作温度-40度C到85度C.本文介绍了AT86RF212的主要特性和方框图,以及基本应用电路图和所用的材料清单.此外还介绍了扩展特性应用电路图.

　　The AT86RF212 is a low-power, low-voltage 700/800/900 MHz transceiver specially

　　designed for the IEEE Standard 802.15.4, ZigBee, 6LoWPAN, and high data rate ISM

　　applications. For the sub-1 GHz bands, it supports low data rates (20 and 40 kbit/s) of

　　the IEEE Standard 802.15.4-2003 [2] and provides optional data rates (100 and 250

　　kbit/s) using O-QPSK, according to the IEEE Standard 802.15.4-2006 [1] and the

　　respective IEEE P802.15.4c Draft Amendment [3]. Furthermore, proprietary High Data

　　Rate Modes up to 1000 kbit/s can be employed.

　　The AT86RF212 is a true SPI-to-antenna solution. RF-critical components except the

　　antenna, crystal, and de-coupling capacitors are integrated on-chip. MAC and AES

　　hardware accelerators improve overall system power efficiency and timing.

　　The AT86RF212 single-chip RF transceiver provides a complete radio interface

　　between the antenna and the microcontroller. It comprises the analog radio part, digital

　　modulation and demodulation including time and frequency synchronization, as well as

　　data buffering. The number of external components is minimized so that only the

　　antenna, a filter (at high output power levels), the crystal, and four bypass capacitors

　　are required. The bidirectional differential antenna pins are used in common for RX and

　　TX, i.e. no external antenna switch is needed. Control of an external power amplifier is

　　supported by two digital control signals (differential operation).

　　The receiver path is based on a low-IF architecture. After channel filtering and downconversion the low-IF signal is sampled and applied to the digital signal processing part. Communication between transmitter and receiver is based on direct sequence spread spectrum with different modulation schemes and spreading codes. The AT86RF212 supports the IEEE 802.15.4-2006 standard mandatory BPSK modulation and optional O-QPSK modulation in the 868.3 MHz and 915 MHz bands. In addition it supports the O-QPSK modulation defined in IEEE P802.15.4c for the Chinese 780 MHz band.

　　For applications not necessarily targeting IEEE compliant networks the radio transceiver supports proprietary High Data Rate Modes based on O-QPSK. A single 128 byte TRX buffer stores receive or transmit data. The AT86RF212 features hardware supported 128 bit security operation. The standalone AES encryption/decryption engine can be accessed in parallel to all PHY operational modes. Configuration of the AT86RF212, reading, and writing of data memory as well as the AES hardware engine are controlled by the SPI interface and additional control signals.

　　On-chip low-dropout voltage regulators provide the analog and digital 1.8 V power supply. Control registers retain their settings in SLEEP mode when the regulators are turned off. The RX and TX signal processing paths are highly integrated and optimized for low power consumption.

　　AT86RF212主要特性:

　　Fully Integrated 700/800/900 MHz-Band Transceiver

　　Chinese WPAN Band from 779 to 787 MHz

　　European SRD Band from 863 to 870 MHz

　　North American ISM Band from 902 to 928 MHz

　　Direct Sequence Spread Spectrum with Different Modulation Schemes and Data Rates

　　BPSK with 20 and 40 kbit/s, compliant to IEEE 802.15.4-2006

　　O-QPSK with 100 and 250 kbit/s, compliant to IEEE 802.15.4-2006

　　O-QPSK with 250 kbit/s, compliant to IEEE P802.15.4c

　　O-QPSK with 200, 400, 500, and 1000 kbit/s PSDU Data Rate

　　Flexible Combination of Frequency Bands and Data Rates

　　Industry Leading Link Budget

　　Receiver Sensitivity up to -110 dBm

　　Programmable TX Output Power up to +10 dBm

　　Low Power Supply Voltage from 1.8 V to 3.6 V

　　Internal Voltage Regulators and Battery Monitor

　　Low Current Consumption

　　SLEEP = 0.2 μA

　　TRX_OFF = 0.4 mA

　　RX_ON = 9.0 mA

　　BUSY_TX = 18 mA at PTX = 5 dBm

　　Digital Interface

　　Registers, Frame Buffer, and AES Accessible through SPI

　　Clock Output with Configurable Rate

　　Radio Transceiver Features

　　Adjustable Receiver Sensitivity

　　Integrated TX/RX Switch, LNA, and PLL Loop Filter

　　Fast Settling PLL Supporting Frequency Hopping

　　Automatic VCO and Filter Calibration

　　Integrated 16 MHz Crystal Oscillator

　　128 byte FIFO for Transmit/Receive

　　IEEE 802.15.4-2006 Hardware Support

　　FCS Computation and Check

　　Clear Channel Assessment

　　Received Signal Strength Indicator, Energy Detection, and Link Quality Indication

　　MAC Hardware Accelerator

　　Automatic Acknowledgement and Retransmission

　　CSMA-CA and LBT

　　Automatic Frame Filtering

　　AES 128 bit Hardware Accelerator (ECB and CBC modes)

　　Extended Feature Set Hardware Support

　　True Random Number Generation for Security Applications

　　TX/RX Indication (External RF Front End Control)

　　Optimized for Low BoM Cost and Ease of Production

　　Low External Component Count: Antenna, Reference Crystal, and Bypass Capacitors

　　Excellent ESD Robustness

　　Industrial Temperature Range from -40°C to +85°C

　　32-pin Low-profile Lead-free Plastic QFN Package, 5.0 x 5.0 x 0.9 mm3

　　Compliant to IEEE 802.15.4-2003, IEEE 802.15.4-2006, IEEE P802.15.4c, ETSI EN 300 220-1, and FCC 47 CFR Section 15.247

　　图1.AT86RF212 方框图

　　图2.AT86RF212基本应用电路图

　　基本应用电路图中的材料清单(BOM):

　　图3. AT86RF212扩展特性应用电路图