A 3 /spl mu/V-offset operational amplifier with 20 nV//spl radic/Hz input noise PSD at DC employing both chopping and autozeroing

Abstract

A 3 /spl mu/V offset op-amp has been designed using both autozeroing and chopping to give 20 nV//spl radic/Hz input noise at DC with low energy at the chopping frequency. The design includes additional circuitry for reduced switching transients. Power consumption is 4 mW from a 5 V supply. Die area is 0.6/spl times/1.12 mm using a 0.6 /spl mu/m double-poly double-metal CMOS process.