原标题：Aaustriamicrosystems AS3900低功耗FSK收发方案

　　Aaustriamicrosystems公司的AS3900是低功耗27MHz FSK收发器,适用于电池工作的短距离范围设备(SRD)的应用.数据速率高达210kbps,器件可配置成收发器,发送器或接收器,工作频段为27.12MHz的ISM.输出功率可调整到0, +5, +10 dBm,并集成了基于OOK的叫醒系统. AS3900的工作电压2.2V-3.6V,接收功耗3.8mA,接收灵敏度-85dBm, 10dBm功率时的发送功耗为4.9mA,关断电流最大为700nA,主要用在设备间短距离数据交换,数据传输,家庭和工业网络控制以及交互式遥控.本文介绍了低功耗星形网络收发器AS3900主要特性, 方框图以及典型应用框图.

　　Low Power 27MHz FSK transceiver with protocol for star network

　　The AS3900 is a low power FSK transceiver ideal for battery-operated short range devices (SRD) applications in which a limited amount of data (data rate up to 210 kbit/s) need to be transferred. The device can be configured as transceiver, transmitter only or receiver only system and operates in one channel in the worldwide ISM band at 27 MHz.

　　The frequency of the external oscillator determines the operating frequency. Use of 27 MHz is in particular advantageous for communication in close proximity of the human body due to the low absorption of the signal by tissue because of the low specific absorption rate at 27 MHz. The device incorporates a serial digital interface (SDI), which enables bidirectional communication with external system components.

　　The integrated real-time-clock, sophisticated wake-up functionality, and link manager enable current efficient control of all communication events and eliminate the need for an expensive microcontroller.

　　The AS3900 supports data transfer in burst mode (bidirectional, controlled by link manager), semi-continuous (bidirectional, controlled by microcontroller) and continuous mode (unidirectional, controlled by microcontroller) and requires only a small number of external components.

　　AS3900主要特性:

　　FSK transceiver

　　Operating frequency 27.12 MHz (ISM - band)

　　Integrated real-time-clock (RTC) based on 32.768kHz XTAL

　　FM deviation selectable (±106 kHz, ±53 kHz)

　　Data transfer in burst mode and (semi-)continuous mode

　　Data rate adjustable to 26.5, 53, 106, 212 kbit/s

　　Low average current consumption in Tx and Rx mode

　　Output power adjustable to 0, +5, +10 dBm

　　Integrated OOK based wake-up system

　　Link manager for control of star network with up to 8 clients

　　Bidirectional serial digital interface (SDI)

　　Main Characteristics

　　Operating temperature range -40℃ to +85℃

　　Operating supply voltage 2.2V to 3.6V (Functional down to 2.0V)

　　Rx current consumption 3.8 mA (typ.)

　　Tx current consumption 4.9 mA@0dBm, 7.6 mA @10dBm

　　Maximum output power 10 dBm (delivered to matching network and antenna)

　　Receiver sensitivity –85 dBm @ 105 kbit/s

　　Polling mode average current consumption typ. 2.5μA

　　Power down current consumption max. 700nA

　　Typ. communication range using small antenna 1.2m@0dBm, 2.5m@10dBm

　　QFN 28 pin (5x5) package

　　Additional Features

　　Reliable pairing and synchronization of master and clients

　　Automatic 16 bit CRC computation in burst mode

　　Auto-acknowledgement and re-transmit

　　Programmable timers to assign variable communication cycle times

　　Reliable system start due to internal POR

　　Programmable microcontroller clock frequency

　　Separate interrupt request line

　　Battery level detector

　　Digital RSSI value accessible in register

　　User programmable Identification with OTP memory (24 bits)

　　AS3900Applications

　　The AS3900 is ideal for reliable low-power short-range data exchange, data transfer among devices in close proximity of human body (Body Area Networks), simple control networks (home, industry), and interactive remote controls. A typical application can be designed in combination with a microcontroller, an antenna and a few additional passive components.

　　图1.低功耗星形网络收发器AS3900方框图

　　图2.低功耗星形网络收发器AS3900典型应用框图

　　图3.AS3900应用框图