SX1210
ADVANCED COMMUNICATIONS & SENSING
3.2.5. Voltage Controlled Oscillator
The integrated VCO requires only two external tank circuit inductors. As the input is differential, the two inductors
should have the same nominal value. The performance of these components is important for both the phase noise
and the power consumption of the PLL. It is recommended that a pair of high Q factor inductors is selected. These
should be mounted orthogonally to other inductors (in particular the LNA biasing inductor) to reduce spurious
coupling between the LNA input and VCO.
For best performance wound type inductors, with tight tolerance, should be used as described in section 7.5.3.
3.2.5.1. SW Settings of the VCO
To guarantee the optimum operation of the VCO over the SX1210’s frequency and temperature ranges, the
following settings should be programmed into the SX1210:
Target channel
(MHz)
Freq_band
863-
870
10
902-
915
00
915-
928
01
950-
960
10
Table 9: MCParam_Freq_band Setting
3.2.5.2. Trimming the VCO Tank by Hardware and Software
To ensure that the frequency band of operation may be accurately addressed by the R, P and S dividers of the
synthesizer, it is necessary to ensure that the VCO is correctly centered. Note that for the reference design (see
section 7.5) no centering is necessary. However, any deviation from the reference design may require the
optimization procedure, outlined below, to be implemented. This procedure is simplified thanks to the built-in VCO
trimming feature which is controlled over the SPI interface. This tuning does not require any RF test equipment,
and can be achieved by simply measuring Vtune, the voltage between pins 6 (LFM) and 7 (LFP).
The VCO is centered if the voltage is within the range:
50 ≤ Vtune ( mV ) ≤ 150 mV
If this inequality is not satisfied then adjust the MCParam_VCO_trim bits from 00 whilst monitoring Vtune. This
allows the VCO voltage to be trimmed in + 60 mV increments. Should the desired voltage range be inaccessible,
the voltage may be adjusted further by changing the tank circuit inductance value. Note that an increase in
inductance will result in an increase Vtune.
Note for mass production: The VCO capacitance is piece to piece dependant. As such, the optimization proposed
above should be verified on several prototypes, to ensure that the population is centered on 100 mV.
3.2.6. PLL Loop Filter
To adequately reject spurious components arising from the comparison frequency Fcomp, an external 2 nd order
loop filter is employed.
Rev 2– Sept 8 , 2008
th
Page 15 of 73
www.semtech.com
相关PDF资料
SX1211SK915 KIT STARTER FOR SX1211 915MHZ
SX1211SKA915 KIT STARTER FOR SX1211 915MHZ
SX1223SK868 KIT STARTER FOR XE1223 868MHZ
SX1701BI085TRT IC AMP 2.5GHZ 5.3V 16-MLPQ
TA002-10002 LED HEATSINK W/FAN 12V 40X10MM
TC620HEPA IC TEMP SNSR 5V DUAL TRIP 8-DIP
相关代理商/技术参数
SX1210I084TRT 制造商:Semtech Corporation 功能描述: 制造商:Semtech Corporation 功能描述:IC SINGLE-CHIP RECEIVER 32-TQFN 制造商:Semtech Corporation 功能描述:SX1210 Series 863 to 960 MHz 3 V 200 kbps Ultra Low Power Receiver - TQFN-32
SX1211 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Lowest Power Integrated UHF Transceiver Short Range Devices
SX1211_08 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Ultra-Low Power Integrated UHF Transceiver
SX1211-11SKA868 功能描述:KIT STARTER FOR SX1211 868MHZ RoHS:是 类别:RF/IF 和 RFID >> RF 评估和开发套件,板 系列:- 标准包装:1 系列:- 类型:GPS 接收器 频率:1575MHz 适用于相关产品:- 已供物品:模块 其它名称:SER3796
SX1211-11SKA915 功能描述:KIT USB FOR SX1211 TXRX 915MHZ RoHS:是 类别:RF/IF 和 RFID >> RF 评估和开发套件,板 系列:- 标准包装:1 系列:- 类型:GPS 接收器 频率:1575MHz 适用于相关产品:- 已供物品:模块 其它名称:SER3796
SX1211I084T 制造商:Semtech Corporation 功能描述:
SX1211I084TRT 功能描述:IC SNGL-CHIP TXRX 32-TQFN RoHS:是 类别:RF/IF 和 RFID >> RF 收发器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:30 系列:- 频率:4.9GHz ~ 5.9GHz 数据传输率 - 最大:54Mbps 调制或协议:* 应用:* 功率 - 输出:-3dBm 灵敏度:- 电源电压:2.7 V ~ 3.6 V 电流 - 接收:* 电流 - 传输:* 数据接口:PCB,表面贴装 存储容量:- 天线连接器:PCB,表面贴装 工作温度:-25°C ~ 85°C 封装/外壳:68-TQFN 裸露焊盘 包装:管件
SX1211I084TRT 制造商:Semtech Corporation 功能描述:GPSS WL SKU APP1