A differential amplifier is an amplifier that amplifies the difference between two voltages and rejects the average or common mode value of the two voltages. The paper presented here is a single input - balanced output cascoded differential amplifier that amplifies a very small signal from the range of nV up to mV with a gain of 46.02db and operating with a constant gain up to 3MHz bandwidth. This work mainly aims at the amplification of very small input voltage and reduction of overall circuit power dissipation maintaining its linearity. Its application is for lower frequency and very small signal amplification. The total circuit power dissipation is only 32.3uW which is appreciable low. The circuit gain is 200 and it is operated with only 1V. The allowable input peak voltage is from 1nV up to 0.7mV and the output swing without distortion is 280mV peak to peak. For low frequency and low signal amplification this small signal amplifier with low power dissipation can lengthen the lifetime of a chip in IC technology which is powered by battery, if the total power dissipation is low.