A write driver circuit

A write driver circuit 90 for use in a magnetic read/write system for writing information to a magnetic storage medium has current sources 75, 85, 77, 86, 83, 91, 81 and 88 comprised of a plurality of transistors connected in series in cascode configurations. This relatively high power write driver circuit is fabricated using a process normally used for fabricating relatively low power write driver circuits. The voltage drop across any one of the transistors of the cascode configurations is limited to meet the requirements of the fabrication process. Also disclosed is; a write driver circuit (20, figure 2) having a variable common mode circuit component (30, figure 2) to enable the circuit common mode output voltage to be varied; a write driver circuit (60, figure 3) having a variable damping resistance circuit component (70, figure 3) to enable the damping resistance of the circuit to be varied; a write driver circuit (80, figure 4) having both a variable common mode circuit component (30, figure 4) and a variable damping resistance circuit component (70, figure 4).