8905 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING

8905
8905 ^{3-PHASE BRUSHLESS DC}
MOTOR CONTROLLER/DRIVER
3-PHASE BRUSHLESS DC MOTOR
CONTROLLER/DRIVER WITH BACK-EMF SENSING
The A8905CLB isw a three-phase brushless dc motor controller/
driver for use with CD-ROM or DVD drives. The three half-bridge
LOAD
SUPPLY
1
V _BB
COMMUTATION
DELAY
24 C _D1
outputs are low on-resistance n-channel DMOS devices capable of
driving up to 1.25 A. The A8905CLB provides complete, reliable,
C _D2 2
23 DATA IN
self-contained back-EMF sensing motor startup and running algorithms.
C _WD 3
22 CLOCK
A programmable digital frequency-locked loop speed control circuit
together with the linear current control circuitry provides precise motor
CST 4
OUTA 5
GROUND 6
T _{GROUND 7}
C _{OUTB 8}
U _{OUTC 99}
D ^{Y CENTERTAP 10}
L _{BRAKE 11}
O _{N CRES 12}
21 CHIP SELECT
20 RESET
19 GROUND
18 GROUND
MUX
17 DATA OUT
BOOST
CHARGE
PUMP
FLL
16 OSCILLATOR
VDD 15
LOGIC
SUPPLY
14 INDEX
13 FILTER
R _{O Dwg. PP-040-1}
P _{E ABSOLUTE MAXIMUM RATINGS}
at T_A = +25°C
D _{C Load Supply Voltage, VBB . . . . . . 14 V}
E _{N Output Current, IOUT . . . . . . . . ±1.25 A}
Logic Supply Voltage, V_DD . . . . 6.0 V
U _{E Logic Input Voltage Range,}
IN ^{VIN . . . . . . . -0.3 V to VDD + 0.3 V}
R _{Package Power Dissipation,}
T ^{E P}D ^{. . . . . . . . . . . . . . . . See Graph}
Operating Temperature Range,
N ^F T_A . . . . . . . . . . . . . . 0°C to +70°C
O ^{E Junction Temperature, TJ . . . +150°Câ€} 
Storage Temperature Range,
C ^{R TS . . . . . . . . . . . . -55°C to +150°C}
† Fault conditions that produce excessive
junction temperature will activate device thermal
IS ^R shutdown circuitry. These conditions can be
tolerated, but should be avoided.
D ^O _{Output current rating may be restricted to a value}
F determined by system concerns and factors.
speed regulation.
A serial port allows the user to program various features and modes
of operation, such as the speed control parameters, startup current limit,
sleep mode, diagnostic modes, and others.
APPLICATIONS
s CD-ROMs
s DVDs
FEATURES
s DMOS Outputs
s Low r_DS(on)
s Startup Commutation Circuitry
s Back-EMF Commutation Circuitry
s Serial Port Interface
s Frequency-Locked Loop Speed Control
s Tachometer Signal Input
s Programmable Start-Up Current
s Diagnostics Mode
s Sleep Mode
s Linear Current Control
s Internal Current Sensing
s Dynamic Braking Through Serial Port
s Power-Down Dynamic Braking
s System Diagnostics Data Out
s Data Out Ported in Real Time
s Internal Thermal Shutdown Circuitry
— ^{These include: system duty cycle and timing,}
ambient temperature, and use of any heatsinking
and/or forced cooling. For reliable operation, the
specified maximum junction temperature should
not be exceeded.
Always order by complete part number, e.g., A8905CLB .