L6327

L6327/L6332 is a BICMOS monolithic integrated cir- cuit GMR differential preamplifier designed for use with four-terminal magneto-resistive GMR read/in- ductive write heads. L6327 is available as either a six (L6327) or four (L6332) channel  device. The L6327 consist of a voltage-sense, current-bias or voltage- bias (selectable), differential input and differential output, low-noise, high bandwidth read amplifier and include fast current switching write drivers which sup- port data rates in excess of 550 Mb/s with 70nH write heads.

The GMR preamplifier provides programmable read current / voltage bias and write current (5 bit DAC for the read bias, 5 bit DAC for the write current), fault detection circuitry and servo writing features. Read amplifier gain, write current wave shape (overshoot, undershoot and damping) can be adjusted and a thermal asperity detection and correction circuit can be enabled and programmed with different thresh- olds (6 bit DAC) through a 16-bit bi-directional serial interface (SDEN, SDATA, SCLK). The L6327 oper- ates from a +5V supply and a -5V supply (nominal). No external components are required as a trimmed or untrimmed resistor for reference current setting is employed.