A8925 ALLEGRO [Allegro MicroSystems], A8925 Datasheet - Page 4

• Manufacturer Part Number: A8925
• Description: 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH LINEAR CURRENT CONTROL AND POWER DMOS OUTPUTS
• Manufacturer: ALLEGRO [Allegro MicroSystems]

8925
3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER
WITH LINEAR CURRENT CONTROL
AND POWER DMOS OUTPUTS
Term.
29–39
7–17
V
SENSE
18
19
20
21
22
23
24
26
28
40
42
43
44
1
2
3
4
6
R
V
S
REF
R
R
POWER GROUND
POWER GROUND
1
2
LOGIC GROUND
LOGIC SUPPLY
Terminal Name
LOAD SUPPLY
ERROR AMP.
REFERENCE
I
1200
ENABLE
OUT
BRAKE
COMP.
FAULT
V
TACH
.
OUT
OUT
OUT
POLE
AMPLIFIER
SENSE
AMPLIFIER
+
_
SENSE
+
H
H
H
-
ERROR
1
2
3
B
C
A
C
1
COMP.
R
3
Function
Power DMOS output.
V
Low-level logic ground.
Power DMOS output.
Active high chip enable.
Power ground and thermal heat sink.
External precision resistor for sense-FET current.
Compensation; error amplifier output.
V
Input that controls the current in the load.
V
A logic low turns OFF all source drivers and turns ON all sink drivers (shorts the windings to
ground).
High-level input from a Hall sensor.
High-level input from a Hall sensor.
High-level input from a Hall sensor.
Power ground and thermal heat sink.
A logic low at this output indicates a thermal shutdown, under -voltage fault, or an invalid Hall
input combination.
Power DMOS output.
Speed reference output; the H
Designates four- or eight-pole motor; Low = 4 pole, High = 8 pole.
CC
REF
BB
C
SEQUENTIAL
2
CHARGE
; high-current 12 V supply for the voice-coil motor.
; low-current 12 V supply for the logic.
PUMP
LOGIC
; voltage input that sets the power output current.
V
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
OUT
SUB
V
BB
Dwg. EP-040
OUT
1
Hall input divided by the number of motor poles.
OUT
are DMOS transistors with a maximum r
of 0.25
diodes clamp transient voltage spikes when
switching inductive loads. Internal charge
pump circuitry is used to drive the gates of
the N-channel source drivers to their required
gate voltages.
monitored by an internal sense amplifier that
produces an output current that is approxi-
mately one twelve hundredth that of the load
current (see Figure). This current is output to
the V
Power Outputs (OUT
Current Control. Current in the load is
C
SENSE
). The power outputs of the A8925CEB
. Intrinsic ground clamp and flyback
terminal and develops a voltage
A
, OUT
Continued next page...
B
, and
DS(on)