Abstract: A spindle motor control for a disk drive including a spindle motor for rotating a data disk at a desired rotational speed, and a data transducer head positionable relative to selected ones of a multiplicity of concentric data tracks formed on a data storage surface of the data disk by a head position actuator structure operating within a head position servo loop, wherein the concentric data tracks are periodically interrupted by a plurality of servo sectors per rotation, each servo sector recorded with head position information.

Abstract: A lateral PNP bipolar transistor includes concentric circular emitter and annular base and dual collector regions. The inner collector region is moderately doped to provide good punch-through and Early voltage performance. The outer collector region is highly doped to provide low collector series resistance. A composite transistor made up of any desired number of individual transistors provides a transistor having a desired current capacity. The transistor annular base cross-section permits very accurate base width control during the manufacturing process.