集成电路中的MOSFET栅控电阻

The MOSFET Gate Controlled Resistor in Intergrated Circuit

工作在非饱和区的MOSFET实际上是一个电压控制电阻,它不仅准确且连续可调.在分析MOSFET栅控电阻的线性特性基础上,通过使用差动运算电路,可抵消掉非线性偶次项;施加适当衬底偏压,可使非线性高次项明显减小.对于兆欧级有源电阻,设计中采用等沟道长度单元MOSFET串联和交叉布局的平衡结构,保证工艺一致.由此制得了线性好、动态范围宽、可调范围大的兆欧级有源电阻.

The Linearity of MOSFET gate voltage-controlled resistors is analysed in this paper. The MOSFET, operated in the nonsaturation region, is basically voltage-controlled resistor. The active R is accuraty and continuously adjustable. The nonlinearity error cancellation of even order terms can be accomplished by using differential operational circuit. The nonlinearity resulting from higher order temrs can be reduved by using proper substrate bias Vks. Based on above analysis we have designed and fabricated the active resistors in order MΩ. The resistor exhibited good linearity and wide dynamic range.