8904, katalog

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PRELIMINARY INFORMATION
(subject to change without notice)
January 24, 2003
8904
3-PHASE BRUSHLESS DC MOTOR
CONTROLLER/DRIVER WITH BACK-EMF SENSING
A8904SLB
(SOIC)
The A8904SLB and A8904SLP are three-phase brushless dc motor
controller/drivers designed for applications where accurate control of
high-speed motors is required. The three half-bridge outputs are low
on-resistance n-channel DMOS devices capable of driving up to 1.25 A.
The A8904 provides complete, reliable, self-contained back-EMF
sensing, motor startup and running algorithms. A programmable digital
frequency-locked loop speed control circuit together with the linear
current control circuitry provides precise motor 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, direction, and diagnostic modes.
The A8904 is fabricated in Allegro’s BCD (Bipolar CMOS DMOS)
process, an advanced mixed-signal technology that combines bipolar,
analog and digital CMOS, and DMOS power devices. The A8904SLB
is provided in a 24-lead wide-body SOIC batwing package. The
A8904SLP is provided in a thin (<1.2 mm), 28-lead SSOP package with
an exposed thermal pad.
Absolute Maximum Ratings
at T
A
= +25°C
Load Supply Voltage, V
BB
. . . . . . . . . .
15 V
Output Current, I
OUT
. . . . . . . . . . . .
±1.4 A*
Logic Supply Voltage, V
DD
. . . . . . . . .
7.0 V
Logic Input Voltage Range, V
IN
(continuous) . . . .
-0.3 V to V
DD
+ 0.3 V
(t
w
<30 ns) . . . . .
-1.0 V to V
DD
+ 1.0 V
Package Power Dissipation, P
D
See Graph
Operating Temperature Range,
T
A
. . . . . . . . . . . . . . . .
-20°C to +85°C
Junction Temperature, T
J
. . . . . . .
+150°C†
Storage Temperature Range,
T
S
. . . . . . . . . . . . . . .
-55°C to +150°C
* 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.
† Fault conditions that produce excessive junction
temperature will activate device thermal shutdown
circuitry. These conditions can be tolerated, but
should be avoided.
Features
Pin-for-pin replacement for A8902CLBA
Startup commutation circuitry
Sensorless commutation circuitry
Option of external sector data tachometer signal
Option of external speed control
Oscillator operation up to 20 MHz
Programmable overcurrent limit
Transconductance gain options: 500 mA/V or 250 mA/V
Programmable watchdog timer
Directional control
Serial Port Interface
TTL-compatible inputs
System diagnostics data out ported in real time
Dynamic braking through serial port or external terminal
Always order by complete part number, e.g.,
A8904SLB
.
8904
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
Functional Block Diagram
(A8904SLB terminal numbers shown)
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2003 Allegro MicroSystems, Inc.
8904
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
LB (SOIC) Package
LP (HTSSOP) Package
A8904SLP
(HTSSOP)
* Measured on “High-K” multi-layer PWB per JEDEC Standard
JESD51-7.
† Measured on typical two-sided PWB with power tabs (LB
package) or thermal pad (LP package) connected to copper foil
with an area of three square inches (1935 mm
2
). See Application
Note 29501.5,
Improving Batwing Power Dissipation
, for
additional information.
www.allegromicro.com
3
8904
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
ELECTRICAL CHARACTERISTICS at T
A
= +25°C, V
DD
= 5.0 V
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max. Units
Logic Supply Voltage
V
DD
Operating
4.5
5.0
5.5
V
Logic Supply Current
I
DD
Operating
—
7.5
10
mA
Sleep mode
—
250
500
µA
Undervoltage Threshold
UVLO
Decreasing V
DD
—
3.6
—
V
Increasing V
DD
—
3.9
—
V
Load Supply Voltage
V
BB
Operating
4.0
—
14
V
Load Supply Current
I
BB
Operating
—
4.0
8.0
mA
Sleep mode
—
20
30
µA
Thermal Shutdown
T
J
—
165
—
°C
Thermal Shutdown Hysteresis
∆
T
J
—20
—°C
Output Drivers
Output Leakage Current
I
DSX
V
BB
= 14 V, V
OUT
= 14 V, sleep mode
—
200
300
µA
V
BB
= 14 V, V
OUT
= 0 V
—
-2.0
-15
µA
Total Output ON Resistance
r
DS(on)
I
OUT
= 600 mA
—
1.0
1.4
Ω
(source + sink + R
S
)
Output Sustaining Voltage
V
DS(sus)
V
BB
= 14 V, I
OUT
= I
OUT
(MAX), L = 3 mH
14
—
—
V
Clamp Diode Forward Voltage
V
F
I
F
= 1.0 A
—
1.25
1.5
V
Control Logic
Logic Input Voltage
V
IN(0)
SECTOR DATA, RESET, CLK,
—
—
0.8
V
V
IN(1)
CHIP SELECT, OSC
2.0
—
—
V
Logic Input Current
I
IN(0)
V
IN
= 0 V
—
—
-0.5
µA
I
IN(1)
V
IN
= 5.0 V
—
—
±1.0
µA
BRAKE Threshold
V
BRK
1.5
1.75
2.0
V
BRAKE Hysteresis Current
I
BRKL
V
BRK
= 750 mV
—
4.0
—
µA
BRAKE Current
I
BRK
Brake set, D2 = 1, I
BRK
= 750 mV
—
20
—
µA
DATA Output Voltage
V
OUT(0)
I
OUT
= 500 µA
—
—
1.5
V
V
OUT(1)
I
OUT
= -500 µA
3.5
—
—
V
C
ST
Current
I
CST
Charging
-9.0
-10
-11
µA
Discharging, V
CST
= 2.5 V
—
500
—
µA
C
ST
Threshold
V
CSTH
High
2.25
2.5
2.75
V
V
CSTL
Low
0.85
1.0
1.15
V
Filter Current
I
FILTER
Charging
-9.0
-10
-11
µA
Discharging
9.0
10
11
µA
Leakage, V
FILTER
= 2.5 V
—
—
±5.0
nA
Filter Threshold
V
FILTERTH
1.57
1.85
2.13
V
C
D
Current
I
CD
Charging
-18
-20
-22
µA
(C
D1
or C
D2
)
Discharging
32
40
48
µA
C
D
Current Matching
—
I
CD(DISCHRG)
/I
CD(CHRG)
1.8
2.0
2.2
—
C
D
Threshold
V
CDTH
2.25
2.5
2.75
V
C
D
Input Leakage
I
CDIL
—
—
1.0
µA
Continued next page …
4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
8904
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
ELECTRICAL CHARACTERISTICS continued
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max. Units
C
WD
Current
I
CWD
Charging, D26 = 0, D27 = 0
-9.0
-10
-11
µA
Charging, D26 = 0, D27 =1
-18
-20
-22
µA
Charging, D26 = 1 D27 = 0
-27
-30
-33
µA
Charging, D26 = 1, D27 =1
-36
-40
-44
µA
C
WD
Threshold Voltage
V
TL
0.22
0.25
0.28
V
V
TH
2.25
2.5
2.75
V
Max. FLL Oscillator Frequency
f
OSC
20*
—
—
MHz
Oscillator High Duration
ton
20
—
—
ns
Oscillator Low Duration
toff
20
—
—
ns
Maximum Output Current
I
OUT
(MAX)
D3 = 0, D4 = 0, D28 = 0
1.0
1.2
1.4
A
D3 = 0, D4 = 1, D28 = 0
0.9
1.0
1.1
A
D3 = 1, D4 = 0, D28 = 0
500
600
700
mA
D3 = 1, D4 = 1, D28 = 0
—
250
—
mA
D3 = 0, D4 = 0, D28 = 1
500
600
700
mA
D3 = 0, D4 = 1, D28 = 1
415
500
585
mA
D3 = 1, D4 = 0, D28 = 1
—
300
—
mA
D3 = 1, D4 = 1, D28 = 1
—
125
—
mA
Transconductance Gain
g
m
D28 = 1
210
250
290
mA/V
D28 = 0
420
500
580
mA/V
Centertap Resistors
R
CT
5.0
10
13
Ω
Back-EMF Threshold with respect
—
5.0
20
37
mV
to
V
CTAP
at FCOM transition
-5.0
-20
-37
mV
Negative current is defined as coming out of (sourcing) the specified device terminal.
* Operation at an oscillator frequency greater than the specified minimum value is possible but not waranteed.
www.allegromicro.com
5
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8904, katalog

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