|
Maxim 公司的MAX7032是基于晶振的分數N的收發(fā)器,能在300MHz－450MHz內發(fā)送和接收ASK/OOK 或多或FSK數據,數據速率高達33kbps (Manchester編碼)或66kbps (NRZ編碼).單電源+2.1V － +3.6V 或+4.5V - +5.5V,典型的RF靈敏度: ASK為－114dBm,FSK 為－110dBm.主要用在工業(yè)控制,家庭自動(dòng)化,遙感技術(shù),車(chē)庫門(mén)禁,本地遙測系統,雙向無(wú)鍵盤(pán)輸入,煙霧報警和遙控等.本文介紹了MAX7032主要特性,方框圖,典型應用電路及其材料清單,以及無(wú)線(xiàn)自動(dòng)讀表參考設計MTR部分電路圖和RDR部分電路圖與相應的材料清單,PCB布局圖. MAX7032是基于晶振的分數N的收發(fā)器，用于在300MHz~450MHz頻率范圍內，發(fā)送和接收ASK / OOK或FSK的數據，其數據傳輸速率高達33kbps（曼徹斯特編碼）或66kbps（NRZ編碼）。此設備可為50Ω負載提供+10 dBm典型輸出功率，FSK數據的典型的靈敏度為-110dBm， ASK數據的典型的靈敏度為-114dBm。MAX7032具有獨立的發(fā)送和接收引腳（PAOUT和LNAIN），并提供內部RF開(kāi)關(guān)，可用于連接發(fā)送/接收引腳與共用天線(xiàn)。 MAX7032的傳輸頻率由一個(gè)16位，分數N鎖相回路（PLL）產(chǎn)生，而，接收機的本地振蕩器（LO）則由一個(gè)整數N PLL產(chǎn)生。這種混合架構，不再需要單獨的傳輸和接收晶體參考振蕩器，因為，分數N PLL可以使傳輸頻率固定在接收頻率的2kHz之內。12位分辨率的分數N PLL可以在fXTAL/4096中使晶振頻率倍頻。保留接收器的，固定的N PLL，則避免了分數N PLL漏電較高的要求，并保持盡可能低的接收器漏電。 
圖1 MAX7032方框圖 MAX7032傳輸PLL的分數N架構，可以對傳輸FSK信號進(jìn)行編，用于準確的頻率偏差，并完全消除了振蕩器牽引FSK信號產(chǎn)生的相關(guān)問(wèn)題。所有產(chǎn)生頻率的元件都集成在芯片上，只需要一個(gè)晶體，一個(gè)10.7MHz IF濾波器，和幾個(gè)分立元件來(lái)實(shí)現完整的天線(xiàn)/數字數據解決方案。 MAX7032采用小型5mm×5mm，32引腳薄型QFN封裝，指定汽車(chē)溫度范圍為-40℃~+125℃。 MAX7032主要特性 • +2.1 V~+3.6 V或+4.5 V~+5.5 V單電源供電 •單晶收發(fā)器 •用戶(hù)可調載波頻率300MHz~450MHz • ASK/OOK和FSK調制 •通過(guò)分數N鎖相環(huán)寄存器，用戶(hù)可調FSK頻偏 •敏捷發(fā)射器頻率合成器，fXTAL/4096載波頻率間隔 •為50Ω負載提供+10 dBm的輸出功率 •集成的TX/RX開(kāi)關(guān) •集成的發(fā)送和接收PLL，VCO和環(huán)路濾波器 • >45分貝鏡像抑制 •典型RF靈敏度 • ASK:-114dBm • FSK:-110dBm •可選擇中頻帶寬與外部濾波器 •高動(dòng)態(tài)范圍的RSSI輸出 •自動(dòng)低功耗管理 • <12.5mA的發(fā)送模式電流 • <6.7mA的接收模式電流 • <23.5µA的尋檢模式電流 • <800nA的關(guān)斷電流 •快速啟動(dòng)功能，<250µs •小尺寸32引腳薄型QFN封裝
圖2 MAX7032典型應用電路圖
圖3 MTR部分電路圖 MAX7032應用 • 2路遙控車(chē)門(mén)開(kāi)關(guān) •安全系統 •家庭自動(dòng)化 •遠程控制 •遙感 •煙霧報警器 •車(chē)庫門(mén)開(kāi)啟 •本地遙測系統 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應用: 2-Way Remote Keyless Entry Security Systems Home Automation Remote Controls Remote Sensing Smoke Alarms Garage Door Openers Local Telemetry Systems
圖1.MAX7032方框圖
圖2.MAX7032典型應用電路圖 圖2典型應用電路材料清單(BOM):
圖3.MTR部分電路圖(1)
圖4.MTR部分電路圖(2)
圖5.MTR部分電路圖(3)
圖6.MTR部分電路圖(4) MTR部分材料清單:
圖7.RDR部分電路圖(1)
圖8.RDR部分電路圖(2)
圖9.RDR部分電路圖(3)
圖10.RDR部分電路圖(4) RDR部分材料清單:
圖11.無(wú)線(xiàn)自動(dòng)讀表參考設計PCB布局圖 詳情請見(jiàn): 
MAX7032.pdf
(301.24 KB)
REFD5391.pdf
(942.57 KB)
來(lái)源：網(wǎng)絡(luò ) |
