MOSCAP linearization and its application in low-power electrocardiogram amplifier

Considerable area occupied by capacitors is one of the main issues in thedesign of many ics, especially in biomedical applications. mim capacitor can be replacedby the moscap to reduce the chip area and cost. although the moscap shows anon-linear behavior, linearization can be performed to some extent using serial and parallelcompensation. in this paper, a new approach is presented, by which the impact of moscapnon-linearity on the thd of the circuit is reduced. the proposed technique is used in anelectrocardiogram amplier. the appropriate structure for each moscap of the amplieris selected by analyzing the non-linear effect of the moscaps on the amplier's outputlinearity. the non-linear effect of moscap is reduced by choosing the appropriate slopesin the moscap capacitance-voltage curve. as a result, the occupied area of the amplieris reduced to less than 10 percent of the area of the amplier with mim capacitors, whilethe thd is not changed considerably. the output thd is 0.65% at 60 hz and the totalpower consumption is 72 nw.