A 273 MHz low noise CMOS MR preamplifier for disk drives

In this paper we present the design for a high speed low noise preamplifier for use with magnetoresistive read elements in disk drive channels. The performance of the reader circuit is comparable with the more expensive current generation of BiCMOS MR preamplifiers. The measured results include a gain of 43 dB, a 3 dB bandwidth of 273 MHz, input-referred voltage noise that is less than 0.57 nV//spl radic/(Hz), and input-referred current noise that is less than 10.54 pA//spl radic/(Hz). The preamplifier has been implemented in a 0.8-/spl mu/m CMOS process and occupies a die area of 1.78/spl times/1.78 mm/sup 2/.