Abstract: A linearly tunable quadrature sinusoidal oscillator for capacitive MEMS sensors detection circuitry is presented. The principle is based on the OTA-C techniques. The frequency is linearly tunable by tuning the Vds of the transistor operating on the triode region, and the oscillator have four outputs with different phase at 90, 180, 270, 360 degrees, respectively. The oscillator is prototyped on a 0.5μm 2P3M CMOS process, and experimental results show that the frequency can be linearly tuned from 0.18MHz to 1.2MHz and the sensitivity to VDD is 8.1%/V.

Key words: OTA-C, oscillator, VCO, sinusoidal, tunable frequency

摘要： 设计了一种用于MEMS传感器电容读出的频率可调的正弦波振荡器。振荡器采用OTA-C结构，通过调节工作于线性区的MOS管的漏源电压来改变OTA的g_m，从而实现对频率的调节。振荡器可输出四路相位分别为90°,180°,270°和360°的振荡信号。芯片在0.5μm2P3MCMOS工艺下设计并流片，测试表明在5V电源电压下振荡频率在180KHz～1.2MHz之间线性可调，振荡频率对于电源电压变化的灵敏度为8.1%/V。

关键词: OTA-C, 振荡器, VCO, 正弦波发生器, 频率可调