A BiCMOS preamplifier/write-driver IC for tape drive

A single-supply 5 V preamplifier IC for magneto-resistive (MR) read element tape drive is described. The IC incorporates six independent read amplifiers, and four independent write drivers. The read amplifier is a fully differential current sense circuit; MR bias current direction steering is incorporated without additional switches in the signal path. In addition the IC incorporates a voltage reference, head diagnostics, control registers, and a serial interface. The entire IC, built in a 1.2 /spl mu/m BiCMOS process, occupies 36 mm/sup 2/. With a 39 ohm read element the measured input referred noise is 1.0 V//spl radic/Hz.