A 500MHz write amplifier for hard disk drives with low output impedance

This paper describes a voltage driver write amplifier used for driving current with very short rise- and falltimes into an inductive write head. Implemented in a 1.0µm BiCMOS process, it has demonstrated rise- and fall-times as short as 0.6ns with a 100mA peak-to-peak output write current suitable to write at data-rates in excess of 500Mb/s.