The preamplifier/write-driver is a small predominantly-analog chip typically bonded directly onto the flex circuit on the actuator and placed as close to the read/write heads as possible [11]. The preamplifier portion provides bias to the read head and must sense and amplify the tiny readback voltages without adding much additional noise. The write-driver provides an adjustable write current plus one or two additional degrees of freedom to carefully shape the leading edge of the transitions in the waveform. The high-frequency electrical characteristics of the front-end circuits, including the transmission lines down the suspension, the impedances looking into the preamplifier/ write-driver, and the read/write elements themselves, must all be carefully designed to maximize performance (data-rate) and minimize cross-coupling. In addition to the preamplifier and write-driver, there is now also a ‘heater driver’ included. This provides power into the thermal actuator on each slider and thus allows the flying height to be accurately adjusted. This IC also plays an important role in protecting the delicate read and write elements from electrical overstress and electrostatic damage.