The ST L6283 is a HDD spindle motor and VCM (voice coil motor) controller from 1999. It was on the board from the Western Digital/La Cie hard drive that I tore down recently. I could not find a data sheet for this part, though several versions of the ‘SMOOTH’ brand of HDD motor controllers were made and there are some datasheets for later versions.

The (4.05mm x 3.8mm) die photo is quite interesting

This is an example of a BCDMOS process which is basically the kitchen sink of processes, it is a BiCMOS process  (Bipolar-CMOS) coupled with a LDMOS (Lateral double-diffused MOS).

On the left the big structure with eleven double bond pads are the LDMOS power transistors that are driving the hard drive spindle motor.  Unfortunately the transistor structures are buried under thick top metal plates and cannot be seen.  There is a good explanation of DMOS transistors and how they work here. As well as the 22 bond wires going to the power transistors, there are another 56 bond wires around the periphery – that is a lot of connections for a spindle motor and the voice coil (read arm actuator) controller.

The process has 3 levels of metal (With a pretty thick top metal) which can be seen in this image (together with polysilicon tracks).  I think the minimum geometry (At polysilicon) is 0.8μm,  the metal 1 tracks in this image are 0.8-1.0μm

In this image you can see all sorts of components used in the analog circuits, resistors, diodes, lateral PNP transistors, vertical Bipolars.

For completeness here is the die mark (that really don’t tell us anything.)

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