一种高线性度电压电流转换电路的设计与实现

介绍了利用CSMC 0.6μm CMOS工艺实现的、应用于电流模逻辑电路中的高线性度电压电流转换(VTC)电路。该电路采用了高增益两级运算放大器,以及工作在弱反型区的MOS管电压电流呈指数律关系实现的PTAT基准电流源。详细分析了电阻与运算放大器的非线性影响因素。测试结果表明,输出的总谐波失真为0.0002%,输入动态范围为0～2.6V,输出电流为50～426μA,PTAT基准电流源对电源变化的灵敏度为0.0217。芯片采用5V供电,功耗约为1.3mW,芯片面积为0.112mm2。

Highly Linear CMOS Voltage-to-Current Converter

A highly linear CMOS voltage-to-current(VTC)converter for current-mode analog and digital integrated circuits is described.By utilizing a high gain operational amplifier(OPA),a Proportional to Absolute Temperature(PTAT)current reference,and a small voltage coefficient poly-silicon resistor,a high linearity is achieved.The resistor and the OPA nonlinearity behavior have been analyzed.The circuit has been implemented in a standard 0.6 μm CMOS technology.The low frequency gain of the OPA exceeds 90 dB.The test result indicates that the total harmonic distortion(THD)is 0.0002%.The common-mode input linearity ranges from 0~2.6 V.Correspondingly,the output current range is 50~426 μA.The sensitivity of the PTAT current reference to VDD is approximately 0.0217.The chip consumes less than 1.3 mW for a 5 V supply,and occupies 0.112 mm2 of area.