NJM3772
DUAL STEPPER MOTOR DRIVER
s
GENERAL DESCRIPTION
The NJM3772 is a stepper motor driver, which circuit is
especially developed for use in microstepping applications in
conjunction with the matching dual DAC (Digital-to-Analog
Converter) NJU39610.
The NJM3772 contains a clock oscillator, which is common
for both driver channels, a set of comparators and flip-flops
implementing the switching control, and two H-bridges with
internal recirculation diodes. Voltage supply requirements are
+5 V for logic and +10 to +45V for the motor. Maximum output
current is 1000mA per channel.
s
PACKAGE OUTLINE
NJM3772D2
NJM3772FM2
s
FEATURES
•
Dual chopper driver
• 1000mA continuous output current per channel
• Specially matched to the Dual DAC NJU39610
• Packages
DIP22 / PLCC28
s
BLOCK DIAGRAM
Phase
1
V
R1
C
1
V
MM1
E
1
NJM3772
V
CC
V
—
+
CC
R
S
Q
M
A1
Logic
M
B1
V
BB1
+
—
V
BB2
M
B2
Logic
M
A2
RC
+
—
S
R
Q
Phase
2
V
R2
C
2
GND
V
MM2
E
2
Figure 1. Block diagram
NJM3772
s
PIN CONFIGURATIONS
Phase
2
27
V
MM2
GND
GND
GND
GND
M
A2
RC
1
C
2 2
V
R2 3
25
24
23
22
V
CC
21
C
1
20
V
R1
19
Phase
1
18
GND
28
V
BB2 5
E
2 6
M
B2 7
M
B1 8
GND
9
E
1 10
V
BB1 11
26
4
3
2
1
V
R2
C
2
RC
V
CC
C
1
V
R1
Phase
1
Phase
2 4
GND
5
GND
6
V
MM2 7
M
A2 8
V
BB2
9
NJM3772FM2
22
21
20
19
NJM
3772D2
17
GND
16
V
MM1
15
M
A1
14
V
BB1
13
E
1
12
M
B1
M
A1 12
GND
13
GND
14
GND
15
GND
16
GND
17
V
MM1 18
E
2 10
M
B2 11
Figure 2. Pin configurations
s
PIN DESCRIPTION
PLCC
DIP
Symbol
Description
1-3, 9,
13-17
28
4
5
6
7
8
10
11
12
18
19
20
21
5, 6
GND
17, 18
8
9
10
11
12
13
14
15
16
19
20
21
M
A2
V
BB2
E
2
M
B2
M
B1
E
1
V
BB1
M
A1
V
MM1
Phase
1
V
R1
C
1
22
23
24
22
1
2
V
CC
RC
C
2
25
26
27
3
4
7
V
R2
Phase
2
V
MM2
Ground and negative supply. Note: these pins are used thermally for heat-sinking.
Make sure that all ground pins are soldered onto a suitably large copper ground
plane for efficient heat sinking.
Motor output A, channel 2. Motor current flows from M
A2
to M
B2
when Phase
2
is HIGH.
Collector of upper output transistor, channel 2. For lowest possible power dissipation, connect a
series resistor R
B2
to V
MM2
. See Applications information, External components.
Common emitter, channel 2. This pin connects to a sensing resistor R
S
to ground.
Motor output B, channel 2. Motor current flows from M
A2
to M
B2
when Phase
2
is HIGH.
Motor output B, channel 1. Motor current flows from M
A1
to M
B1
when Phase
1
is HIGH.
Common emitter, channel 1. This pin connects to a sensing resistor R
S
to ground.
Collector of upper output transistor, channel 1. For lowest possible power dissipation, connect a
series resistor R
B1
to V
MM1
. See Applications information, External components.
Motor output A, channel 1. Motor current flows from M
A1
to M
B1
when Phase
1
is HIGH.
Motor supply voltage, channel 1, +10 to +40 V. V
MM1
and V
MM2
should be connected together.
Controls the direction of motor current at outputs M
A1
and M
B1
. Motor current flows from M
A1
to M
B1
when Phase
1
is HIGH.
Reference voltage, channel 1. Controls the threshold voltage for the comparator and hence the
output current.
Comparator input channel 1. This input senses the instantaneous voltage across the sensing
resistor, filtered by an RC network. The threshold voltage for the comparator is V
CH1
= 0.18 • V
R1
[V],
i.e. 450 mV at V
R1
= 2.5 V.
Logic voltage supply, nominally +5 V.
Clock oscillator RC pin. Connect a 15 kohm resistor to V
CC
and a 3300 pF capacitor to ground to
obtain the nominal switching frequency of 26.5 kHz.
Comparator input channel 2. This input senses the instantaneous voltage across the sensing
resistor, filtered by an RC network. The threshold voltage for the comparator is V
CH2
= 0.18 • V
R2
[V],
i.e. 450 mV at V
R2
= 2.5 V.
Reference voltage, channel 2. Controls the threshold voltage for the comparator and hence the
output current.
Controls the direction of motor current at outputs M
A2
and M
B2
. Motor current flows from M
A2
to M
B2
when Phase
2
is HIGH.
Motor supply voltage, channel 2, +10 to +40 V.V
MM1
and V
MM2
should be connected together.
NJM3772
s
FUNCTIONAL DESCRIPTION
Each channel of the NJM3772 consists of the following sections: an output H-bridge with four transistors, capable
of driving up to 1000 mA continuous current to the motor winding; a logic section that controls the output transis-
tors; an S-R flip-flop; and a comparator. The clock-oscillator is common to both channels.
Constant current control is achieved by switching the output current to the windings. This is done by sensing the
peak current through the winding via a current-sensing resistor R
S
, effectively connected in series with the motor
winding during the turn-on period. As the current increases, a voltage develops across the sensing resistor, which
is fed back to the comparator. At the predetermined level, defined by the voltage at the reference input V
R
, the
comparator resets the flip-flop, which turns off the output transistors. The current decreases until the clock oscillator
triggers the flip-flop, which turns on the output transistors again, and the cycle is repeated.
The current paths during turn-on, turn-off and phase shift are shown in figure 3. Note that the upper recirculation
diodes are connected to the circuit externally.
External recirculation diodes
V
MM
1
R
B
V
BB
2
3
R
S
Motor Current
1
2
3
Fast Current Decay
Slow Current Decay
Time
Figure 3. Output stage with current paths
during turn-on, turn-off and phase shift.
NJM3772
s
ABSOLUTE MAXIMUM RATINGS
Parameter
Pin no. DIP package
Symbol
Min
Max
Unit
Voltage
Logic supply
Motor supply
Output stage supply
Logic inputs
Comparator inputs
Reference inputs
Current
Motor output current
Logic inputs
Analog inputs
Temperature
Operating junction temperature
Storage temperature
Power Dissipation (Package Data)
Power dissipation at T
GND
= +25°C, DIP and PLCC package
Power dissipation at T
GND
= +125°C, DIP package
Power dissipation at T
GND
= +125°C, PLCC package
22
7, 16
9, 14
4, 19
2, 21
3, 20
8, 11, 12, 15
4, 19
2, 3, 20, 21
V
CC
V
MM
V
BB
V
I
V
C
V
R
I
M
I
I
I
A
T
j
T
S
P
D
P
D
P
D
0
0
0
-0.3
-0.3
-0.3
-1200
-10
-10
-40
-55
-
-
-
7
45
45
6
V
CC
7.5
+1200
-
-
+150
+150
5
2.2
2.6
V
V
V
V
V
V
mA
mA
mA
°C
°C
W
W
W
s
RECOMMENDED OPERATING CONDITIONS
Parameter
Symbol
Min
Typ
Max
Unit
Logic supply voltage
Motor supply voltage
Output stage supply voltage
Motor output current
Junction temperature **
Rise and fall time, logic inputs
Oscillator timing resistor
** See operating temperature chapter
V
CC
V
MM
V
BB
I
M
T
J
t
r
, t
f
R
T
4.75
10
V
MM
- 0.5
-1000
-20
-
2
5
-
-
-
-
-
15
5.25
40
V
MM
+1000
+125
2
20
V
V
V
mA
°C
µs
kΩ
Phase
1
V
R1
19
20
C
1
21
V
MM1
16
E
1
13
NJM3772
I
CC
V
CC
V
22
—
+
CC
Pin no.
refers to DIP-package
R
S
Q
15
Logic
12
M
A1
M
B1
V
BB1
V
BB2
M
B2
M
A2
IM
I OL
| V
MA
– V
MB
|
t
on
50 %
t
off
14
15 k
Ω
+
R
T
—
9
11
Logic
8
t
V
E
R
B
I
RC
RC
1
+
—
t
d
S
R
Q
V
3 300 pF
CH
V
CC
C
T
4
Phase
2
I
I
I
IH
I
IL
I
A
V
I
V
V
IH
3
V
R2
2
C
2
I
C
I
A
5, 6, 17, 18
GND
7
V
MM2
10
E
2
I MM
1 kΩ
t
V
A
V
R
V
CH
V
C
820 pF
R
C
V
E
V
M
V
MA
V
BB
V
MM
IL
C
C
R
S
1
f
s
=
t + t
on
off
D=
t
on
t
on +
t
off
Figure 4. Definition of symbols
Figure 5. Definition of terms
NJM3772
s
ELECTRICAL CHARACTERISTICS
Electrical characteristics over recommended operating conditions, unless otherwise noted. -20°C< T
J
< 125°C
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
General
Supply current
Total power dissipation
Total power dissipation
Thermal shutdown junction temperature
Turn-off delay
Logic Inputs
Logic HIGH input voltage
Logic LOW input voltage
Logic HIGH input current
Logic LOW input current
Comparator Inputs
Threshold voltage
| V
CH1
- V
CH2
| mismatch
Input current
Reference Inputs
Input resistance
Input current
Motor Outputs
Lower transistor saturation voltage
Lower transistor leakage current
Lower diode forward voltage drop
Upper transistor saturation voltage
Upper transistor saturation voltage
Upper transistor leakage current
Chopper Oscillator
Chopping frequency
I
CC
P
D
P
D
Note 4.
V
MM
= 12 V, I
M1
= I
M2
= 750 mA.
R
B
= 0.68 ohm. Notes 2, 3, 4, 5.
V
MM
= 12 V, I
M1
= 1000 mA, I
M2
= 0 mA.
R
B
= 0.47 ohm. Notes 2, 3, 4, 5.
T
A
= +25°C, dV
C
/dt
≥
50 mV/µs,
I
M
= 100 mA. Note 3.
-
-
-
-
-
60
1.8
1.8
160
1.4
75
2.1
2.2
-
2.0
mA
W
W
°C
µs
t
d
V
IH
V
IL
I
IH
I
IL
V
CH
V
CH,diff
I
C
R
R
I
R
V
I
= 2.4 V
V
I
= 0.4 V
R
C
= 1 kohm, V
R
= 2.50 V
R
C
= 1 kohm
2.0
-
-
-0.4
430
-
-10
-
-
-
-
-
-
-
-
25.0
-
-
-
-
450
1
-
5
0.5
0.6
-
1.2
0.6
0.8
-
26.5
-
0.8
20
-
470
-
1
-
1.0
0.9
700
1.5
0.9
1.1
700
28.0
V
V
µA
mA
mV
mV
µA
kohm
mA
V
µA
V
V
V
µA
kHz
T
A
= +25°C
V
R
= 2.50 V
I
M
= 750 mA
V
MM
= 41 V, V
E
= V
R
= 0 V, V
C
= V
CC
I
M
= 750 mA
I
M
= 750 mA. R
B
= 0.68 ohm. Note 5
I
M
= 750 mA. R
B
= 0.47 ohm. Note 3, 5
V
MM
V
BB
= 41 V, V
E
= V
R
= 0 V, V
C
= V
CC
f
s
C
T
= 3300 pF, R
T
= 15 kohm
s
THERMAL CHARACTERISTICS
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
Thermal resistance
Rth
J-GND
Rth
J-A
Rth
J-GND
Rth
J-A
DIP package
DIP package. Note 2
PLCC package
PLCC package. Note 2
-
-
-
-
11
40
9
35
-
-
-
-
°C/W
°C/W
°C/W
°C/W
Notes
1. All voltages are with respect to ground. Currents are positive into, negative out of specified terminal
2. All ground pins soldered onto a 20 cm
2
PCB copper area with free air convection, T
A
= +25°C
3. Not covered by final test program
4. Switching duty cycle D = 30%, f
s
= 26.5 kHz
5. External resistors R
B
for lowering of saturation voltage
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