A Method to Reduce the Effect of the Switching Noise in Analog-Mixed Circuits

Sample-hold is one of the basic non-linear functions in analog-mixed circuits. Switching noise can critically affect the operation for such a function, particularly in case of current sample-hold, if no effective measures are taken to reduce it. In this paper, a method for an efficient reduction of the effect of the switching noise is proposed. The principle of this method is to bias a transistor in the operation region where it has a weak transconductance and an attenuating voltag e transfer characteristic, and use this device to absorb the switching noise, in order to protect the critical circuit nodes. T his method can be implemented very easily without need of any devices requiring linearity or precision. A current memory cell is desig ned with this method and the simulation results show that the switching noise causes much less negative effect to the circuit operation.