L7250 Datasheet, PDF (1/46 Pages) STMicroelectronics – 5V & 12V SPINDLE AND VCM MOTORS DRIVER

L7250
5V & 12V SPINDLE AND VCM MOTORS DRIVER
PRODUCT PREVIEW
s 12V & 5V (±10%) OPERATION
s REGISTER BASED ARCHITECTURE
s 3 WIRE SERIAL COMMUNICATION
INTERFACE UP TO 33 MHZ
s BCD TECHNOLOGY
Spindle Motor Controller
s INTERNAL POWER DEVICE 0.9 OHM MAX
VALUE @ 125°C (SINK+SOURCE)
s 2.5A PEAK CURRENT CAPABILITY
s ST SMOOTHDRIVE SINUSOIDAL PWM
COMMUTATION
s DEDICATED ADC FOR POWER SUPPLY
VOLTAGE COMPENSATION
s SPINDLE CURRENT LIMITING VIA FIXED
FREQUENCY PWM OF SPINDLE POWER
OUTPUTS AT THE SMOOTHDRIVE PWM
RATE
s SYNCHRONOUS RECTIFICATION DURING
PWM TO REDUCE POWER DISSIPATION
s CURRENT SENSING VIA EXTERNAL
CURRENT SENSE RESISTOR
s INDUCTIVE SENSE POSITION START UP
DRIVEN BY µPROCESSOR
s SPINDLE BRAKING DURING POWER DOWN
CONDITION
Voice Coil Motor Driver with Ramp Load/Unload
s INTERNAL POWER DEVICE 0.9 OHM MAX
VALUE @ 125°C (SINK+SOURCE)
s 2A PEAK CURRENT CAPABILITY
s 15 BIT LINEAR DAC FOR CURRENT
COMMAND, WITH INTERNAL REFERENCE
VOLTAGE
s SENSE AMPLIFIER GAIN SWITCH
s CLASS AB OUTPUT STAGE WITH ZERO
DEAD-BAND AND MINIMAL CROSSOVER
DISTORTION
s RAMP LOAD AND UNLOAD CAPABILITY AS
WELL AS CONSTANT VOLTAGE RETRACT
s EXTERNAL CURRENT SENSE RESISTOR IN
SERIES WITH MOTOR.
s HIGH CMRR (>70DB) AND PSRR (>60DB)
SENSE AMP
s EXTERNAL CURRENT CONTROL LOOP
COMPENSATION
s HIGH BANDWIDTH VCM CURRENT
CONTROL LOOP CAPABILITY
s HIGH PSRR, LOW OFFSET, LOW DRIFT GM
LOOP
TQFP64
ORDERING NUMBER: L7250
s VCM VOLTAGE MODE, CONTROLLED BY
VCM DAC
s GM LOOP OFFSET CALIBRATION SCHEME
INCLUDES A COMPARATOR ON THE
ERROR AMP
Auxiliary Functions
s 3.3V AND 1.8V LINEAR REGULATOR
CONTROLLER
s NEGATIVE VOLTAGE REGULATOR
s INTERNAL ISOFET 0.1 OHM @125C
s POWER MONITOR OF 12V, 5V, 3.3V AND
1.8V
s SHOCK SENSOR CIRCUIT TAKES INPUTS
FROM PIEZO OR CHARGING ELEMENT
s 10 BIT ADC WITH 4 MUXED INPUTS
s THERMAL SENSE CIRCUIT AND OVER
TEMPERATURE SHUT DOWN
s CHARGE PUMP BOOST VOLTAGE
GENERATOR FOR HIGH SIDE GATE DRIVE
s ANALOG PINS AVAILABLE TO ENTER
SIGNALS TO BE CONVERTED BY THE
INTERNAL ADC
DESCRIPTION
L7250 is a power IC for driving the SPINDLE and
VCM motors, suitable for 5V & 12V application. The
spindle system includes integrated power FETs
which are driven using ST's Smoothdrive pseudo-si-
nusoidal commutation technology. The voice coil mo-
tor (VCM) system includes integrated power FETs,
as well as ramp load and unload capability. Linear
3.3V and1.8V voltage regulators are included, as well
as a negative regulator.
Power monitoring of VCC5, VCC12, and of the two
positive voltage regulators is also included.L7250
uses a 3 wire serial interface: S_DATA, S_CLK and
S_ENABLE
July 2001
1/46
This is preliminary information on a new product now in development. Details are subject to change without notice.