2-Phase Excitation
SMA7036M
2-Phase Stepper Motor Unipolar Driver IC
sAbsolute
Maximum Ratings
Parameter
Motor supply voltage
Control supply voltage
FET Drain-Source voltage
TTL input voltage
SYNC terminal voltage
Reference voltage
Sense voltage
Output current
Power dissipation
Channel temperature
Storage temperature
Ambient operating temperature
Symbol
V
CC
V
S
V
DSS
V
IN
V
SYNC
V
REF
V
RS
I
O
P
D1
P
D2
T
ch
T
stg
T
a
Ratings
46
46
100
−0.3
to +7
−0.3
to +7
−0.3
to +7
−5
to +7
1.5
4.0 (T
a
=25°C)
28 (T
c
=25°C)
150
−40
to +150
−20
to +85
Units
V
V
V
V
V
V
V
A
W
W
°C
°C
°C
sElectrical
Characteristics
Parameter
Control supply current
Control supply voltage
FET Drain-Source
voltage
Symbol
I
S
Condition
V
S
V
DSS
Ratings
min
typ
10
V
S
=44V
24
V
S
=44V, I
DSS
=250
µ
A
0.6
I
D
=1A, V
S
=10V
1.1
I
SD
=1A
250
V
DSS
=100V, V
S
=44V
2
I
D
=1A
0.8
V
DSS
=100V
2
V
DSS
=100V
0.8
I
D
=1A
±1
V
S
=44V, V
I
=0 or 5V
4.0
Synchronous chopping mode
0.8
Asynchronous chopping mode
0.1
V
S
=44V, V
YS
=5V
−0.1
V
S
=44V, V
YS
=0V
0
Reference voltage input
4.0
Output FET OFF
±1
No synchronous trigger
40
Resistance between GND and REF terminal at synchronous trigger
1.5
V
S
=24V, I
D
=1A
0.5
V
S
=24V, I
D
=1A
0.9
V
S
=24V, I
D
=1A
0.1
V
S
=24V, I
D
=1A
12
V
S
=24V
5.5
2.0
V
mA
V
V
V
max
15
44
Units
mA
V
V
V
V
10
100
DC characteristics
Condition
V
DS
FET ON voltage
Condition
V
SD
FET diode forward voltage
Condition
I
DSS
FET drain leakage current
Condition
V
IH
Condition
Active H
V
IL
Condition
V
IH
IN terminal
Condition
Active L
V
IL
Input
current
Input
voltage
SYNC terminal
Condition
I
I
Condition
V
SYNC
H
Condition
V
SYNC
L
µ
A
µ
A
AC characteristics
Condition
I
SYNC
H
Condition
Input
current
I
SYNC
L
Condition
V
REF
Input
Condition
voltage
V
REF
Condition
REF terminal
I
REF
Input
Condition
current
R
REF
Internal
resistance Condition
T
on
Condition
T
r
Condition
Switching time
T
stg
Condition
T
f
Condition
Chopping OFF time
T
OFF
Condition
µ
A
Ω
µ
s
µ
s
12
SMA7036M
2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)
SMA7036M
sInternal
Block Diagram
1
6
5
8
14
10
15
IN A
IN B
Vs
1, 6, 10, 15pin
Description of pins
Reg.
Oscillator
MOSFET
gate drive
circuit
Synchronous
chopping
circuit
Reg.
Chopping
blanking timer
(5
µ
s typ)
+
−
Oscillator
MOSFET
gate drive
circuit
Synchronous
chopping
circuit
Chopping
blanking timer
(5
µ
s typ)
+
−
1pin
6pin
10pin
15pin
Excitation input
Active H
Active L
OUT A
OUT A
OUT A
OUT A
OUT B
OUT B
OUT B
OUT B
Chopping
OFF timer
(12
µ
s typ)
Chopping
OFF timer
(12
µ
s typ)
SYNC A
SYNC B
REF A
REF B
GND A
GND B
7
Rs A
2
4
3
13
12
11
9
sDiagram
of Standard External Circuit (Recommended Circuit Constants)
Vcc (46V max)
+
Excitation signal time chart
8
V
S
2
Sync
A
SMA7036M
Vb (5V)
11
PchMOS
r1
Rs
A
7
Rs
Ref
A
Ref
B
3
13
Rs
B
9
Rs
G
A
4
G
B
12
Sync
B
IN
B
14
IN
B
IN
A
5
IN
A
1
6
10
15
Rs B
2-phase excitation
clock
IN
A
IN
B
0
H
L
1
H
H
2
L
H
3
L
L
0
H
L
1
H
H
:
r
1
:
r
2
R
S
(1 to 2W) :
PchMOS :
Inv
:
8kΩ
2kΩ (VR)
1Ω typ
HN1J02FU (Toshiba)
7404
r2
Inv
Disable (High Active)
SMA7036M
13
2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)
SMA7036M
sExternal
Dimensions
(Unit: mm)
Epoxy resin package
31
±0.2
10.2
±0.2
30°
4
±0.2
2.5
±0.2
3
±0.6
1.2
±0.1
(5.9)
(7.5)
1.6
±0.6
0.62
±0.1
1.16
±0.15
P2.03
±0.1
×14=28.42
12 3 · · · · · · · 15
1 2 3 · · · · · · · 15
(4.6)
+0.2
0.55
–0.1
8.5max
Lot No.
Part No.
1.45
±0.15
6.7
±0.5
(9.7)
+0.2
0.65
–0.1
1.16
+0.2
–0.1
P2.03
±0.1
×14=28.42
31.3
+0.2
+0.2
0.55
–0.1
4
±0.7
Forming No. No.1054
(3)
Forming No. No.1055
14
SMA7036M
2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)
SMA7036M
Application Notes
sOutline
SMA7036M is a stepper motor driver IC developed to reduce
the number of external parts required by the conventional
SMA7029M. This IC successfully eliminates the need for some
external parts without sacrificing the features of SMA7029M.
The basic function pins are compatible with those of SMA7029M.
Connect TTL or similar to the SYNC terminals and switch the
SYNC terminal level high or low.
When the motor is not running, set the TTL signal high (SYNC
terminal voltage: 4 V or more) to make chopping synchronous.
When the motor is running, set the TTL signal low (SYNC terminal
voltage: 0.8 V or less) to make chopping asynchronous. If chop-
ping is set to synchronous when the motor is running, the motor
torque deteriorates before the coil current reaches the set value.
If no abnormal noise occurs when the motor is not running,
ground the SYNC terminals (TTL not necessary).
sNotes
on Replacing SMA7029M
SMA7036M is pin-compatible with SMA7029M. When using
the IC on an existing board, the following preparations are nec-
essary:
(1) Remove the resistors and capacitors attached for setting
the chopping OFF time. (r
3
, r
4
, C
1
, and C
2
in the catalog)
(2) Remove the resistors and capacitors attached for preventing
noise in the detection voltage V
RS
from causing malfunction-
ing and short the sections from which the resistors were re-
moved using jumper wires. (r
5
, r
6
, C
3
, and C
4
in the catalog)
(3) Normally, keep pins 2 and 11 grounded because their func-
tions have changed to synchronous and asynchronous
switching (SYNC terminals). For details, see "Circuit for Pre-
venting Abnormal Noise When the Motor Is Not Running (Syn-
chronous circuit)." (Low: asynchronous, High: synchronous)
SYNC_A
TTL, etc.
SYNC_B
SMA7036M
SYNC voltage : Low
→
Chopping asynchronous
SYNC voltage : High
→
Chopping synchronous
sCircuit
for Preventing Abnormal Noise When the
Motor Is Not Running (Synchronous Circuit)
A motor may generate abnormal noise when it is not running.
This phenomenon is attributable to asynchronous chopping be-
tween phases A and B. To prevent the phenomenon, SMA7036M
contains a synchronous chopping circuit. Do not leave the SYNC
terminals open because they are for CMOS input.
5V
The built-in synchronous chopping circuit superimposes a trigger
signal on the REF terminal for synchronization between the two
phases. The figure below shows the internal circuit of the REF
terminal. Since the
∆
V
REF
varies depending on the values of R1
and R2, determine these values for when the motor is not run-
ning within the range where the two phases are synchronized.
SMA7036M
R1
V
REF
R2
3
14
REF_A
REF_B
40
Ω
(typ.)
40
Ω
(typ.)
V
REF
waveform
V
REF
0
ONE SHOT
(tw=2
µ
S)
FET B/B
gate drive signal
To comparator
(high impedance)
Sync/async
switching signal
ONE SHOT
(tw=2
µ
S)
FET A/A
gate drive signal
sSynchronous
circuit operating waveform
V
REF
Phase A
0
V
RS
V
REF
Phase B
0
V
RS
Synchronous circuit OFF
Synchronous circuit ON
SMA7036M
15
2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)
SMA7036M
sDetermining
the Output Current
Fig. 1 shows the waveform of the output current (motor coil cur-
rent). The method of determining the peak value of the output
current (I
O
) based on this waveform is shown below.
(Parameters for determining the output current I
O
)
V
b
: Reference supply voltage
r
1
,r
2
: Voltage-divider resistors for the reference supply voltage
R
S
: Current sense resistor
(1) Normal rotation mode
I
O
is determined as follows when current flows at the maximum
level during motor rotation. (See Fig.2.)
r
2
V
b
................................................................
(1)
I
O
≅
•
r
1
+r
2
R
S
(2) Power down mode
The circuit in Fig.3 (r
x
and T
r
) is added in order to decrease the
coil current. I
O
is then determined as follows.
I
OPD
≅
1+
1
r
1
(r
2
+r
X
)
r
2
•
r
X
1
1
r
1
tively.
V
b
R
s
•
I
OPD
−1
−
1
r
2
•
Fig. 1 Waveform of coil current (Phase A excitation ON)
I
O
Phase A
0
Phase A
Fig. 2 Normal mode
V
b
(5
V
)
r
1
3,(13)
r
2
7,(9)
R
S
V
b
......................................................... (2)
R
S
Equation (2) can be modified to obtain equation to determine rx.
r
X
=
Fig. 3 Power down mode
V
b
(5
V
)
r
1
3,(13)
r
x
Power down
signal
T
r
R
S
r
2
7,(9)
Fig. 4 and 5 show the graphs of equations (1) and (2) respec-
Fig. 4 Output current I
O
vs. Current sense resistor R
S
Fig. 5 Output current I
OPD
vs. Variable current sense resistor rx
4
2.0
2
r
2
· V
b
r
1
+r
2
R
S
r
1
=510Ω
r
2
=100Ω
r
x
=∞
V
b
=5V
I
O
=
Output current I
OPD
(A)
Output current I
O
(A)
3
1.5
R
S
=0.5Ω
1
· V
b
r
1
(r
2+
r
X
)
R
S
1+
r
2 ·
r
X
r
1
=510Ω
r
2
=100Ω
V
b
=5V
I
OPD
=
1.0
R
S
=0.8Ω
R
S
=1Ω
1
0.5
0
0
1
2
3
4
00
200
400
600
800
1000 1200
Current sense resistor R
S
(Ω)
Variable current sense resistor r
X
(Ω)
16
SMA7036M
