Spare parts technique has been widely used in digital designs. As memory cells are more susceptible to defects and faults than logic cells, redundancy has been extensively used for enhancing defect and fault tolerance through repair by spare replacement. The technique also aims yield increase, and points to be a very good solution since density integration gets ever higher. In this work, we propose the use of spare parts to develop reliable analog circuits, thus increasing fault tolerance by choosing among many identical blocks, the best ones that will compose the circuit. An example using a mixed-signal FIR filter is presented, showing that the technique can easily be adapted to help increase yield of analog circuits, too.