Allegro A8925CEB Datasheet
8925
3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER
WITH LINEAR CURRENT CONTROL
8925
AND POWER DMOS OUTPUTS
3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER
WITH LINEAR CURRENT CONTROL
AND POWER DMOS OUTPUTS
Data Sheet
26301.30
The A8925CEB is a DMOS three-phase brushless dc motor controller/driver designed for use in Winchester disk drives and other data
storage applications. The power output stages are capable of ±4 A
output currents and have DMOS power outputs with less than 0.25 Ω
r
for low power dissipation. Intrinsic ground clamp and flyback
DS(on)
diodes protect the output drivers when switching inductive loads.
Thermal shutdown circuitry is provided to protect the device from excessive junction temperature.
A transconductance amplifier is used to linearly regulate the load
current and control motor speed. Internal current-sensing circuitry
eliminates the need for external sense resistors. Analog and digital
control circuitry provide complete sequencing of the output drivers as
well as providing brake, disable, and tachometer functions. A FAULT
output flag indicates the presence of an under-voltage condition on the
12 V supply, excessive junction temperature, or an invalid Hall input
combination. The A8925CEB’s commutation logic is compatible with
motors that have digital Hall-effect sensors with 120° of electrical
separation. Internal charge pump circuitry is provided to drive the N-
POWER
GROUND
POWER
GROUND
C
NC
ENABLE
OUT
5
6
4
7
8
9
10
11
12
CHARGE PUMPS
13
14
15
16
17
SUB
18
SENSE
V
19
COMP.
+
20
REFERENCE
LOGIC GROUND
LOGIC SUPPLY
2
3
CC
V
BB
V
22
21
ERROR AMP
LOAD SUPPLY
B
OUT
1
23
BRAKE
POLE
44
43
SEQUENCING
AND CONTROL
25
24
1
H
TACH
CIRCUITRY
NC
A
OUT
NC
424140
27
26
2
NC
H
FAULT
39
38
37
36
35
34
33
32
31
30
29
SUB
28
3
H
Dwg. PP-034
POWER
GROUND
POWER
GROUND
channel DMOS source drivers to their required gate voltages.
ABSOLUTE MAXIMUM RATINGS
AT T
= +25°C
A
Load Supply Voltage, VBB.....................14 V
Output Current, I
Logic Supply Voltage, V
.......................... ±4.0 A
OUT
.....................14 V
CC
Logic Input Voltage Range,
V
................................ -0.3 V to +6.0 V
IN
Package Power Dissipation,
P
......................................... See Graph
D
Operating Temperature Range,
T
..................................... 0°C to +70°C
A
Junction Temperature, T
...............+150°C†
J
Storage Temperature Range,
T
................................ -55°C to +150°C
S
† Fault conditions that produce excessive
DISCONTINUED PRODUCT
junction temperature will activate device thermal
shutdown circuitry. These conditions can be
tolerated, but should be avoided.
Output current rating may be restricted to a value
determined by system concerns and factors.
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.
— FOR REFERENCE ONLY
The A8925CEB is provided in a 44-lead PLCC power package for
surface-mount applications. The copper batwing provides for maximum allowable package power dissipation in the smallest possible
construction.
FEATURES
■ DMOS Outputs
■ Low r
■ Linear Current Control
■ Internal Commutation Circuitry
■ Internal Current Sensing
■ Thermal Shutdown Circuitry
■ Under Voltage Detection Circuitry
■ Fault Output Flag
■ Power Surface-Mount Package
Always order by complete part number: A8925CEB .
- 0.25 Ω Maximum
DS(on)
8925
3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER
WITH LINEAR CURRENT CONTROL
AND POWER DMOS OUTPUTS
12.5
10
7.5
5.0
2.5
0
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
25
ELECTRICAL CHARACTERISTICS AT T
50 75 100 125 150
= +25°C, V
A
R = 6°C/W
θJT
R = 30°C/W
θJA
TEMPERATURE IN °C
CC
= V
Dwg. GP-020B
BB =
12 V
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Logic Supply Voltage V
Load Supply Voltage V
Supply Current I
Thermal Shutdown T
CC
BB
CC
J
Operating 10 12 14 V
Operating 10 12 14 V
Operating — 30 50 mA
V
= 0 V — 2.0 4.0 mA
ENABLE
— 165 — °C
Output Drivers
Output ON Resistance r
Output Sustaining Voltage V
DS(on)
DS(sus)
Clamp Diode Forward Voltage V
Output Leakage Current I
F
DSX
I
= ±4.0 A, Pulse Test — 0.20 0.25 Ω
OUT
I
= 4.0 A, L = 2 mH 14 —— V
OUT
IF = ±4.0 A — 1.5 2.0 V
V
= 14 V — 10 300 µA
OUT
= 0 V — -10 -300 µA
V
OUT
Control Logic
Logic Input Voltage V
Logic Input Voltage V
Logic Input Current I
V
V
I
IN(0)
IN(1)
IN(0)
IN(1)
IN(0)
IN(1)
ENABLE, POLE ——0.8 V
2.4 ——V
BRAKE ——0.8 V
3.0 ——V
VIN = 0.8 V ——-1.0 µA
VIN = 2.4 V ——1.0 µA
NOTE: Negative current is defined as coming out of (sourcing) the specified device terminal. Continued next page...
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1990, 1995 Allegro MicroSystems, Inc.
8925
3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER
WITH LINEAR CURRENT CONTROL
AND POWER DMOS OUTPUTS
ELECTRICAL CHARACTERISTICS CONTINUED
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Logic Output Voltage V
(FAULT, TACH)
OUT(0)
V
OUT(1)
Error Amplifier
Input Bias Current I
Input Offset Voltage V
Input Common-Mode Voltage Range V
Error Voltage Gain A
Unity Gain Bandwidth BW — 1.0 — MHz
Common-Mode Rejection Ratio CMRR — 80 — dB
Power Supply Rejection Ratio PSRR — 50 — dB
IB
OS
IC
VD
Miscellaneous
Current Sense Gain A
Current-Sense Matching — I
Under-Voltage Trip Point V
Hall Input Current I
Hall Input Threshold V
Hall Input Pull-Up Resistance R
IN(0)
I
IN(1)
iCS
CC
IN
PU
I
= 3 mA ——0.8 V
OUT
I
= -50 µA 2.0 ——V
OUT
VCM = 0.01 V — 5.0 10 µA
VCM = 1.0 V — 3.0 5.0 mV
0.01 — 6.0 V
V
/ V
, V
= 1.0 V — 80 — dB
CM
I
OUT
OUT
S OUT
S IN
= -1.0 A 1/1k 1/1.2k 1/1.4k —
= -1.0 A — ±3.0 ±5.0 %
8.0 — 9.5 V
VIN = 0 V — -500 -1000 µA
VIN = 5.0 V — -250 -500 µA
— 3.8 — V
— 25 — kΩ
NOTE: Negative current is defined as coming out of (sourcing) the specified device terminal.
COMMUTATION TRUTH TABLE
Hall Sensor Inputs Outputs
H
1
High Low High High High High High Low Z
High Low Low High High High High Z Low
High High Low High High High Z High Low
Low High Low High High High Low High Z
Low High High High High High Low Z High
Low Low High High High High Z Low High
High High High High High Low Z Z Z
Low Low Low High High Low Z Z Z
X X X Low High X Z Z Z
XXXXLowXLowLowLow
X = Irrelevant
Z = High Impedance
H
2
H
ENABLE BRAKE FAULT OUT
3
OUTBOUT
A
C
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