A high CMRR current mode CMOS preamplifier for magnetic recording systems

This paper presents a high CMRR current mode CMOS preamplifier for a dual stripe magnetoresistive (DSMR) read head for magnetic recording systems. The current mode design approach a avoids high impedance nodes in the circuit and helps in achieving a high bandwidth. The differential circuit topology and the common mode negative feedback greatly improve the CMRR and PSRR. The preamplifier is designed using a 0.5 /spl mu/m CMOS technology. The achieved 3-dB bandwidth is 120 MHz at a gain of 45 dB, the CMRR and PSRR are 62 and 74 dB respectively. The equivalent input noise voltage is 1.83 nV//spl radic/Hz.