Si9993CS

Vishay Siliconix

FaxBack 408-970-5600, request 70653

S-60752–Rev. A, 05-Apr-99

www.siliconix.com

1

12-V VCM/Spindle Motor Driver for Large Capacity HDD

FEATURES

DESCRIPTION

The Si9993CS consists of a 3-phase brushless dc motor

(spindle) PWM controller and a linear/PWM transconductance

stage suitable for driving a voice coil motor (head actuator). To

meet the power handling capability required for a high

capacity hard disk drive, both drivers utilize external LITTLE

FOOT half-bridges (Siliconix Si9942 recommended). A

separate LITTLE FOOT PMOS switch (Si9430) is used as a

synchronous rectifier in place of the usual Schottky blocking

diode.

Si9993CS is manufactured in a junction-isolated BiC/DMOS

process (JIBCD15) and is available in a 64-pin SQFP

package, specified to operate over the commercial (0

°C to

70

°C) temperature range.

• 12-V Motor Supply

• Blocking Schottky Diode Replaced by External Synchronous Rectifier

• Spindle Motor Driver Features:

– External LITTLE FOOT® Drivers for High Current/Power Application

– Constant Off-Time PWM Current Drive Minimizing Power Dissipation

– Sensorless Motor Commutation Immune to PWM Noise

– Externally Controlled Start-Up/Run Function

– Low-Jitter Commutation Output for External Speed Control

– Level Shifting Buffer Amplifier for PWM DAC

– Adjustable Output Slew Rate Control

– Unique Commutation Driver Minimizing Audible Noise

– Programmable Phase Advance for High Speed Motor

– Speed Triggered Motor Brake for Enhanced Reliability

• Voice Coil Motor Driver Features:

– External LITTLE FOOT Drivers for High Current/Power Application

– Low Crossover Distortion in Linear Mode (Class AB)

– Selectable Constant Frequency PWM or Linear Operation

– Programmable Retract Voltage Clamp

– Level Shifting Buffer Amplifier for PWM DAC

– Direct VCM Retract Control Input

– Current Sense Output for Enhanced Servo Control

– Fixed PWM Output Slew Rate Limit

• System Manager Features:

– Power-On Reset Generator

– Adjustable System Voltage Monitor

– 2.3/5.0-V±5%, 150 ppm/

°C Reference Output for External PWM DAC

– Programmable Timer for Head Retract and Spindle Brake Delay

– Built-In Test Ability

• 3-Wire Synchronous Serial Data Interface

• Internal Registers and Address Decoding with Full Readback Capability

Si9993