Data-Surface Servo Format - Fujitsu MHT2080AH - 80GB 5400 RPM PATA Hard Drive Product Manual

Theory of Device Operation
(5) Spindle motor control circuit
The spindle motor control circuit controls the sensor-less spindle motor. A
spindle driver IC with a built-in PLL(FLL) circuit that is on a hardware unit
controls the sensor-less spindle motor.
(6) Driver circuit
The driver circuit is a power amplitude circuit that receives signals from the
spindle motor control circuit and feeds currents to the spindle motor.
(7) VCM current sense resistor (CSR)
This resistor controls current at the power amplifier by converting the VCM
current into voltage and feeding back.

4.7.2 Data-surface servo format

Figure 4.7 describes the physical layout of the servo frame. The three areas
indicated by (1) to (3) in Figure 4.7 are described below.
(1) Inner guard band
This area is located inside the user area, and the rotational speed of the VCM can
be controlled on this cylinder area for head moving.
(2) Data area
This area is used as the user data area SA area.
(3) Outer guard band
This area is located at outer position of the user data area, and the rotational speed
of the spindle can be controlled on this cylinder area for head moving.
4-14 C141-E195-02EN