A 2-to-2.4-GHz differentially-tuned fractional-N frequency synthesizer for DVB tuner applications

This paper describes the design of a fractional-N frequency synthesizer for digital video broadcasting-terrestrial (DVB-T) receivers.Transfer functions in differentially-tuned PLL are derived and loop parameters are designed. In addition,a fully-differential charge pump is presented.An 8/9 high speed prescaler is analyzed and the design considerations for the CML logic are also presented.Test results show that the RMS phase error is less than 0.7°in integer-N mode and less than 1°in fractional-N mode.The...     

一种应用于DVB调谐器中的2-2.4-GHz分数频率综合器设计

摘要—本文设计了一个应用在DVB 调谐器中的分数频率综合器。详细比较了全差分频率综合器和单端调谐频率综合器的传输函数。在此基础上设计了频率综合器的环路参数。除此之外详细描述了全差分电荷泵的实现方式,并提出了改进的开关以提高电荷泵的线性度。设计了同步8/9 预分频器并讨论了设计细节。频率综合器环路带100 kHz,参考杂散小于-63 dBc。在1 MHz 频偏处相位噪声小于-110 dBc/Hz。100 Hz-100 MHz均方根积分噪声在整数分频模式小于0.7度。在分数分频模式小于1度。本文所涉及到的频率综合器在SMIC 0.18-μm CMOS 工艺下流片实现,电源电压为1.8-V,电流消耗为10 mA,面积为1-mm2。