一种射频接收芯片中的低相位噪声压控振荡器

本文介绍了一种适用于ASK幅移键控接收器芯片中锁相环电路,集成于芯片内的LC压控振荡器,它的LC振荡电路采用了一种增强型的特别结构。芯片采用锁相环电路来产生本振信号。接收器通过它工作在290MHz到470MHz的ISM频段。锁相环中的VCO采用了差分对结构的LC压控振荡器结构,在1V到5V的控制电压下能产生290到470的可调频率,输出功率为2.20到2.30dBm。该VCO采用了增强型结构的LC振荡电路以得到更高的Q值来减小相位噪声,采用这种特殊结构,它能在433MHz载波的100kHz偏移范围内实现-99.7dBc/Hz的相位噪声。与普通LC振荡电路结构相比,该结构能使VCO相位噪声减小3dBc以上。且由于该电路由较少的有源器件组成,因此该VCO有着非常低的功耗和成本。

A low Phase Noise VCO using Enhanced LC Resonator in an integrated ASK Receiver

An integrated LC Voltage Controlled Oscillator(VCO)using enhanced resonator has been implemented in a PLL (Phase Locked Loop) for an ASK (Amplitude Shift Key) Receiver IC chip. The on-chip PLL performs the LO (Local Oscillator) generation, through which the receiver can work at ISM band frequencies from 290MHz to 470 MHz. The VCO presented in this paper has a tunable frequency over 290-470 MHz under control voltage from 1V to 5V, with an output power of 2.20-2.30dBm. In order to obtain a high Q quality an enhanced LC resonator has been adopted in this VCO. With this special architecture, it can realize a phase noise figure less than -99.7dBc/Hz at 100 kHz-offset frequencies from a 433MHz carrier. Compared with the common LC resonator VCO, its phase noise has dropped more than 3dBc/Hz. Consisting of only a few active devices, the VCO has very low power dissipation and a low cost.