The SLA7024M, SLA7026M, and SMA7029M are designed for
high-efficiency and high-performance operation of 2-phase, unipolar
stepper motors. An automated, innovative packaging technology
combined with power FETs and monolithic logic/control circuitry ad-
vances power multi-chip modules (PMCMsTM) toward the complete
integration of motion control. Highly automated manufacturing tech-
niques provide low-cost and exceptionally reliable PMCMs suitable for
controlling and directly driving a broad range of 2-phase, unipolar
stepper motors. The three stepper motor multi-chip modules differ
primarily in output current ratings (1.5 A or 3.0 A) and package style.
All three PMCMs are rated for an absolute maximum limit of 46 V
and utilize advanced NMOS FETs for the high-current, high-voltage
driver outputs. The avalanche-rated (
100 V) FETs provide excellent
ON resistance, improved body diodes, and very-fast switching. The
multi-chip ratings and performance afford significant benefits and
advantages for stepper drives when compared to the higher dissipation
and slower switching speeds associated with bipolar transistors.
Normally, heat sinks are not required for the SLA7024M or SMA7029M.
The SLA7026M, in demanding, higher-current systems designs,
necessitates suitable heat transfer methods for reliable operation.
Complete applications information is given on the following pages.
PWM current is regulated by appropriately choosing current-sensing
resistors, a voltage reference, a voltage divider, and RC timing net-
works. The RC components limit the OFF interval and control current
decay. Inputs are compatible with 5 V logic and microprocessors.
BENEFITS AND FEATURES
s
Cost-Effective, Multi-Chip Solution
s
`Turn-Key' Motion-Control Module
s
Motor Operation to 3 A and 46 V
s
3
rd
Generation High-Voltage FETs
s
100 V, Avalanche-Rated NMOS
s
Low r
DS(on)
NMOS Outputs
s
Advanced, Improved Body Diodes
s
Single-Supply Motor/Module
Operation
SMA7029M
HIGH-CURRENT PWM, UNIPOLAR STEPPER
MOTOR CONTROLLER/DRIVERS
Data Sheet
28201
Always order by complete part number:
Part Number
Package
Output Current
SLA7024M
18-Lead Power-Tab SIP
1.5 A
SLA7026M
18-Lead Power-Tab SIP
3.0 A
SMA7029M
15-Lead SIP
1.5 A
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25
C
Load Supply Voltage, V
BB
. . . . . . . . . . . . 46 V
FET Output Voltage, V
DS
. . . . . . . . . . . 100 V
Control Supply Voltage, V
CC
. . . . . . . . . . 46 V
Peak Output Current, I
OUTM
(t
w
100
s)
SLA7024M . . . . . . . . . . . . . . . . . . . . . 3.0 A
SLA7026M . . . . . . . . . . . . . . . . . . . . . 5.0 A
SMA7029M . . . . . . . . . . . . . . . . . . . . 3.0 A
Continuous Output Current, I
OUT
SLA7024M . . . . . . . . . . . . . . . . . . . . . 1.5 A
SLA7026M . . . . . . . . . . . . . . . . . . . . . 3.0 A
SMA7029M . . . . . . . . . . . . . . . . . . . . 1.5 A
Input Voltage Range, V
IN
. . . . -0.3 V to 7.0 V
Reference Voltage, V
REF
. . . . . . . . . . . 2.0 V
Package Power Dissipation, P
D
.
See Graph
Junction Temperature, T
J
. . . . . . . . . +150
C
Operating Temperature Range,
T
A
. . . . . . . . . . . . . . . . . . . . -20
C to +85
C
Storage Temperature Range,
T
stg
. . . . . . . . . . . . . . . . . . -40
C to +150
C
s
Half- or Full-Step Unipolar Drive
s
High-Efficiency, High-Speed PWM
s
Dual PWM Current Control (2-Phase)
s
Programmable PWM Current Control
s
Low Component Count PWM Drive
s
Low Internal Power Dissipation
s
Heat Sinking (Normally) Unnecessary
s
Electrically Isolated Power Tab
s
Logic IC- and
P-Compatible Inputs
s
Machine-Insertable Package
REFERENCE A
V
REF
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Dwg. PK-007
OUT A
OUTB
SENSEA
GROUND A
V
REF
V
CC
+
+
OUTA
CONTROL/LOGIC
OUTB
GROUND B
REFERENCE B
CNTRL SPLY
IN A
IN B
SENSE B
OFF DELAYA
OFF DELAY B
CONTROL/LOGIC
TM
SLA7024M, SLA7026M,
AND
SMA7029M
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
TM
SLA7024M, SLA7026M,
AND
SMA7029M
HIGH-CURRENT PWM,
UNIPOLAR STEPPER MOTOR
CONTROLLER/DRIVERS
SLA7024M and SLA7026M FUNCTIONAL BLOCK DIAGRAM
Note that channels A and B are electrically isolated.
SMA7029M FUNCTIONAL BLOCK DIAGRAM
Note that except for the control supply, channels A and B are electrically isolated.
+
13
Dwg. FK-005-1
+
8
12
9
15
10
14
11
REG.
8
5
3
2
4
6
7
1
VCC
SENSE
GROUND
OFF-TIME
DELAY
CONTROL
SUPPLY
IN A/B
OUTA/B
OUT A/B
REFERENCE
CHANNEL A PIN NUMBERS
CHANNEL B PIN NUMBERS
+
14
Dwg. FK-005
+
12
15
10
11
18
16
17
13
REG.
7
6
5
3
2
4
1
9
8
V
CC
IN
A/B
SENSE
GROUND
OFF-TIME
DELAY
CONTROL
SUPPLY
IN
A/B
OUT
A/B
OUT
A/B
REFERENCE
CHANNEL A PIN NUMBERS
CHANNEL B PIN NUMBERS
Copyright 1994 Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
TM
SLA7024M, SLA7026M,
AND
SMA7029M
HIGH-CURRENT PWM,
UNIPOLAR STEPPER MOTOR
CONTROLLER/DRIVERS
2.4 k
R
+
14
Dwg. EK-008
+
12
15
10
18
16
17
13
REG.
V
CC
V
BB
A
B
OUT
A
IN B
IN B
11
B
OUT
V +5 V
+5 V
R 510
R 100
47 k
R
470 pF
C
C 2200 pF
R
1
S
TO
CHANNEL
A
V
REF
SENSE
t d
3
b
1
2
5
3
1
TYPICAL STEPPER MOTOR APPLICATIONS
(Half of Each Device Shown)
SLA7024M and SLA7026M
TRUTH TABLES
(Device Types as Designated)
WAVE DRIVE (FULL STEP)
for SLA7024M and SLA7026M
Sequence
0
1
2
3
0
Input A
H
L
L
L
H
Input A
L
L
H
L
L
Input B
L
H
L
L
L
Input B
L
L
L
H
L
Output ON
A
B
A
B
A
HALF-STEP OPERATION (2-1-2 SEQUENCE)
for SLA7024M, SLA7026M, and SMA7029M
Sequence
0
1
2
3
4
5
6
7
0
Input A
H
H
L
L
L
L
L
H
H
Input A or t
dA
*
L
L
L
H
H
H
L
L
L
Input B
L
H
H
H
L
L
L
L
L
Input B or t
dB
*
L
L
L
L
L
H
H
H
L
Output(s) ON
A
AB
B
A B
A
AB
B
A B
A
*Logic signals to external open-collector inverter connected to t
dA
and t
dB
.
2-PHASE (FULL STEP) OPERATION
for SLA7024M and SLA7026M
Sequence
0
1
2
3
0
Input A
H
L
L
H
H
Input A
L
H
H
L
L
Input B
H
H
L
L
H
Input B
L
L
H
H
L
Outputs ON
AB
A B
AB
A B
AB
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