AN1139

Manufacturer Part NumberAN1139
DescriptionL6254 - L6268 - L6269 12V DISK DRIVE POWER COMBO IC
ManufacturerSTMicroelectronics
AN1139 datasheet
 


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The Devices integrate into a single chip both SPINDLE and VCM controllers as well as power stages. The
device is designed for 12V disk drive application requiring up to 2.0A of Spindle and 1.5 of Vcm peak
current. A serial port with up to 25MHz capability provides easy interface to the microprocessor. A register
controlled Frequency Locked Loop (FLL) allows flexibility in setting the Spindle Speed. Integrated BEMF
processing, digital masking, digital commutation delay, and sequencing minimize the number of external
components required.
Power On Reset (POR) circuitry is included. Upon detection of a low voltage
condition, POR is asserted, the internal registers are reset, and Spindle power circuitry is tri-stated. The
BEMF is rectified providing power for the actuator retraction followed by dynamic Spindle braking. The
device is built in BICMOS technology allowing dense digital / analog circuitry to be combined with a high
power DMOS output stage. Minor differences characterize the three devices. The L6254 serial interface
lines SDEN, SCLK and SDATA are 5V compatible. The L6268 and L6269 serial interface lines are 3.3V
compatible. The L6268 is also provided with a slug mounted on the back of the package to improve power
dissipation.
C H A R G E
C S
P U M P
S W 1
ISO DRIVER
S D A T A
SERIAL
S C L K
INTERFACE
S D E N
TR_12V
SUPPLY
FAULT
M O N I T O R S
TR_5V
May 1999
12V DISK DRIVE POWER COMBO IC
SPINDLE SEQUENCER
FREQUENCY
LOCK LOOP
PROCESSING
START-UP
RE_SYNC
ZERO CROSS
DETECTION
DYNAMIC /
R E V E R S E
B R A K E
V C M C U R R E N T
REGISTERS
CONTROL
PSM / LIN
V C M
CALIBRATION
RECTIFICATION
T H E R M A L
R E F E R E N C E
14 BIT
V O L T A G E
V C M D A C
G E N E R A T O R
SUPPLY
APPLICATION NOTE
L6254 - L6268 - L6269
by Carlo Vertemara
O U T _ A
B E M F
C T A P
O U T _ B
RSENSE
O U T _ C
SPINDLE
ISENSE
C U R R E N T
CONTROL
PWM / LIN
V C M _ A +
PARKING
V C C
B E M F
V C M _ A -
V C M _ G N D
SENSE_IN-
A=4
SENSE_IN+
AN1139
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