The KA3120 is an ASIC combination chip, which was designed for the HDD, includes the following functions: spindle motor drive, voice coil motor drive, retract and power management.
To drive and control the spindle, the digital ASIC provides the appropriate control signals (Start up, commutation, speed control) to the KA3120. The spindle motor condition is monitored by the FG output and the motor speed control is accomplished via the PWMSP input. The ASIC controls the voice coil motor current via PWMH and PWML inputs and the power management circuit always monitors the power supply voltages.

FEATURES
SPINDLE MOTOR DRIVE PART

• Soft switching
• Spindle brake after retract
• Adjustable brake delay time
• 2.0A max. current power driver
• Low output saturation voltage: 1V typical @1.6A
• PWM decoder & filter for soft switching
• The digital circuit (ASIC) based start-up, commutation and motor speed control

VOICE COIL MOTOR DRIVE PART

• Trimmed low offset current
• 1.2A max. current power driver
• Gain selection and adjustable gain
• Automatic power down retract function
• Class AB linear amplifier with no dead zone
• Low output saturation voltage: 0.8V typical @1.0A
• Internal full bridge with VPNP (Vertical PNP) & NPN
• VCM offset monitoring

POWER MONITORING

• Power on reset with delay
• Hysteresis on both power comparators
• Over temperature & over current shut down
• 5V and 12V power monitor threshold accuracy ±2%

PACKAGE
• 48QFPH (48 pin quad flat package heat-sink)

APPLICATION
• Hard disk drive (HDD) products