SAA7335 Datasheet, PDF (19/36 Pages) NXP Semiconductors – DSP for CD and DVD-ROM systems

Philips Semiconductors
DSP for CD and DVD-ROM systems
Preliminary specification
SAA7335
OPERATIONAL MODES
The motor servo has a number of operational modes controlled by the motor mode register MOTOR4.
POWER LIMIT
To start and stop the spindle motor, a fixed positive or negative voltage is applied to the motor. This voltage can be
programmed as a percentage of the maximum possible voltage via the motor output configuration register (MOTOR4) to
limit current drain during start and stop. The following power limits are possible:
• 100% of maximum (no power limit)
• 75% of maximum
• 50% of maximum
• 37% of maximum.
LOOP CHARACTERISTICS
The gain and crossover frequencies of the motor control loop can be programmed via the motor gain and bandwidth
register MOTOR2.
22 kΩ
MOTO1
+
–
10 nF
VDD ^VSS
22 kΩ
MOTO1
22 kΩ
22 kΩ
10 nF
VSS
VSS
M
+
–
22 kΩ
22 kΩ
22 kΩ
+
MOTO2
–
10 nF
VSS
M
VSS
VDD
MGA363 - 1
Fig.13 Motor pulse density application diagrams.
1997 Aug 11
19