中文摘要：

介绍了一款用于分数分频频率综合器的具有量化噪声抑制功能的小数分频器。使用4/4.5双模预分频器,将分频步长降为0.5,使带外相位噪声性能提高6 dB。ΣΔ调制器和分频器的配合使用一种非常简单的编程方式。采用同步电路消除异步分频器的抖动。采用该分频器的频率综合器在SMIC 0.18μm RF工艺下实现,芯片面积为1.47 mm×1 mm。测试结果表明,该频率综合器可以输出1.2～2.1 GHz范围的信号。测试的带内相位噪声小于-97 dBc/Hz,在1 MHz频偏处的带外相位噪声小于-124 dBc/Hz。在1.8 V的电源电压下,消耗的电流为16 mA。

英文摘要：

This paper presents a fractional frequency divider with quantization noise suppression used in a fractional-N frequency synthesizer.By using a 4/4.5 dual-modulus prescaler,the step size of the divider is reduced to 0.5 and thus the out-of-band phase noise performance is improved by 6 dB.A simple programming method is introduced which is important for the cooperation of the divider and the ΣΔ modulator.A synchronizer is adopted to eliminate the jitter accumulation of asynchronous dividers.A frequency synthesizer using the frequency divider presented here is implemented in SMIC 0.18 μm RF process and the die size is 1.47 mm×1 mm.Measurement results show that the tuning range of the frequency synthesizer is from 1.2 GHz to 2.1 GHz.The measured in-band phase noise is less than-97 dBc/Hz@10 kHz,the out-of-band phase noise at 1 MHz frequency offset is less than-124 dBc/Hz.The frequency synthesizer consumes 16 mA from a 1.8 V voltage supply.