Maxim 公司的MAX7032是基于晶振的分数N的收发器,能在300MHz－450MHz内发送和接收ASK/OOK 或多或FSK数据,数据速率高达33kbps (Manchester编码)或66kbps (NRZ编码).单电源+2.1V － +3.6V 或+4.5V - +5.5V,典型的RF灵敏度: ASK为－114dBm,FSK 为－110dBm.主要用在工业控制,家庭自动化,遥感技术,车库门禁,本地遥测系统,双向无键盘输入,烟雾报警和遥控等.本文介绍了MAX7032主要特性,方框图,典型应用电路及其材料清单,以及无线自动读表参考设计MTR部分电路图和RDR部分电路图与相应的材料清单,PCB布局图.

The MAX7032 crystal-based, fractional-N transceiver is designed to transmit and receive ASK/OOK or FSK data in the 300MHz to 450MHz frequency range with data rates up to 33kbps (Manchester encoded) or 66kbps (NRZ encoded). This device generates a typical output power of +10dBm into a 50Ω load, and exhibits typical sensitivities of -114dBm for ASK data and -110dBm for FSK data. The MAX7032 features separate transmit and receive pins (PAOUT and LNAIN) and provides an internal RF switch that can be used to connect the transmit and receive pins to a common antenna.

The MAX7032 transmit frequency is generated by a 16-bit, fractional-N, phase-locked loop (PLL), while the receiver’s local oscillator (LO) is generated by an integer-N PLL. This hybrid architecture eliminates the need for separate transmit and receive crystal reference oscillators because the fractional-N PLL allows the transmit frequency to be set within 2kHz of the receive frequency. The 12-bit resolution of the fractional-N PLL allows frequency multiplication of the crystal frequency in steps of fXTAL/4096. Retaining the fixed-N PLL for the receiver avoids the higher current drain requirements of a fractional-N PLL and keeps the receiver current drain as low as possible.

The fractional-N architecture of the MAX7032 transmit PLL allows the transmit FSK signal to be programmed for exact frequency deviations, and completely eliminates the problems associated with oscillator-pulling FSK signal generation. All frequency-generation components are integrated on-chip, and only a crystal, a 10.7MHz IF filter, and a few discrete components are required to implement a complete antenna/digital data solution.

The MAX7032 is available in a small 5mm x 5mm, 32-pin,thin QFN package, and is specified to operate in the automotive -40°C to +125°C temperature range.

MAX7032主要特性:

♦ +2.1V to +3.6V or +4.5V to +5.5V Single-Supply Operation

♦ Single Crystal Transceiver

♦ User-Adjustable 300MHz to 450MHz Carrier Frequency

♦ ASK/OOK and FSK Modulation

♦ User-Adjustable FSK Frequency Deviation Through Fractional-N PLL Register

♦ Agile Transmitter Frequency Synthesizer with fXTAL/4096 Carrier-Frequency Spacing

♦ +10dBm Output Power into 50Ω Load

♦ Integrated TX/RX Switch

♦ Integrated Transmit and Receive PLL, VCO, and Loop Filter

♦ > 45dB Image Rejection

♦ Typical RF Sensitivity*

ASK: -114dBm

FSK: -110dBm

♦ Selectable IF Bandwidth with External Filter

♦ RSSI Output with High Dynamic Range

♦ Autopolling Low-Power Management

♦ < 12.5mA Transmit-Mode Current

♦ < 6.7mA Receive-Mode Current

♦ < 23.5μA Polling-Mode Current

♦ < 800nA Shutdown Current

♦ Fast-On Startup Feature, < 250μs

♦ Small 32-Pin, Thin QFN Package

MAX7032应用:

2-Way Remote Keyless Entry

Security Systems

Home Automation

Remote Controls

Remote Sensing

Smoke Alarms

Garage Door Openers

Local Telemetry Systems

图1.MAX7032方框图

图2.MAX7032典型应用电路图
图2典型应用电路材料清单(BOM):


图3.MTR部分电路图(1)

图4.MTR部分电路图(2)

图5.MTR部分电路图(3)

图6.MTR部分电路图(4)
MTR部分材料清单:


图7.RDR部分电路图(1)

图8.RDR部分电路图(2)


图9.RDR部分电路图(3)

图10.RDR部分电路图(4)

RDR部分材料清单:




图11.无线自动读表参考设计PCB布局图
详情请见:
http://datasheets.maxim-ic.com/en/ds/MAX7032.pdf
和
http://pdfserv.maxim-ic.com/en/an/REFD5391.pdf