Widely Programmable High-Frequency Active RC Filters in CMOS Technology
Widely Programmable High-Frequency Active RC Filters in CMOS Technology
复制标题
采用 CMOS 技术的广泛可编程高频有源 RC 滤波器
DOI：
10.1109/tcsi.2008.2001759
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
S. Pavan
中科院分区：
文献类型：
--
作者：
T. Laxminidhi;V. Prasadu;S. Pavan
我们提出了一种电路技术，使可广泛编程的高频有源RC滤波器能够在CMOS工艺中实现。一个具有数字可编程3分贝带宽(从44 MHz到300 MHz)的五阶切比雪夫梯形滤波器被用作工具来验证我们的想法。该运算放大器采用前馈补偿，以实现高直流增益和宽带宽。积分电阻由三极管工作的MOSFET和固定多晶硅电阻串联而成。基于电荷泵的伺服回路将积分电阻伺服到稳定的片外电阻。在运算放大器和积分电阻上采用恒定电容定标原理，使带宽在7倍范围内定标时保持频率响应的形状。该滤波芯采用0.18微米的CMOS工艺设计，在1.8V电源电压下功耗为54 mW，动态范围为56.6分贝。
We propose a circuit technique that enables the realization of widely programmable high-frequency active RC filters in CMOS technology. A fifth-order Chebyshev ladder filter having a digitally programmable 3-dB bandwidth (from 44 to 300 MHz) is used as a vehicle to validate our ideas. The opamp uses feedforward compensation for achieving high dc gain and wide bandwidth. The integrating resistors are realized as a series combination of a triode-operated MOSFET and a fixed polysilicon resistor. A charge-pump-based servo loop servoes the integrating resistor to a stable off-chip resistor. The principle of ldquoconstant capacitance scalingrdquo is applied to the opamp and the integrating resistors so that the shape of the frequency response is maintained when the bandwidth is scaled over a 7 times range. The filter core, designed in a 0.18-mum CMOS process, consumes 54 mW from 1.8-V supply and has a dynamic range of 56.6 dB.