The Circuit Design Of Low Offset DRAM Sense Amplifier

DRAM is a significant section of the Memory industry.As the critical circuit of DRAM,SA plays a crutial part in data reading.In DRAM,the bit lines linked to the SA exist.The sense amplifier is used to distinguish the two bit lines' voltage difference and amplify the voltage difference in order to make it could be identified by the peripheral circuit.In the manufacturing process of DRAM,because of the different threshold voltage of transistors,two MOSFETs which are theoretically the same may be adapted,the misadjustment noise in the operation of the sensitive amplifier will generate because of this,which will lead to the incorrect amplification and error reading of data.So as to cost down the influence of offset voltage on the reading operation,this paper comes up with a sensitive amplifier circuit which is low offset.The main contents is described from the following aspects.First,the essay presents the construction,course of work and the cause of offset voltage of the traditional SA,and the advantages and disadvantages of the existing solution of offset voltage of DRAM SA are simulated and analyzed,including OCSA,OMCSA and BRV?SA circuits.Finally,On the basis of the above analysis,a SA circuit with low offset is proposed.In compensation stage,the input-output is shorted.Besides,current mirror are combined,which is to compensate the different voltage,so as to reduce the offset voltage.The proposed circuit was simulated under the conditions of 65 nm CMOS process,1.2V power supply voltage,TT process Angle and.25 ?,including the simulation analysis of the circuit's offset voltage,speed,accuracy and power consumption under different bit line load capacitance.Take a load capacitance of 100 f F as an example,the consequences indicate that,contrasted with OCSA,OMCSA and BRV?SA compensation circuits,the proposed low offset sense amplifier reduces the offset voltage by 90%,80% and 75% respectively,increases the reading speed by21.2%,10% and 13.1% respectively,and reduces the power consumption by 25.2%,15.1%and 8% respectively.