NJM3771
s
PIN CONFIGURATIONS
M
B1 1
NC
1
MB
1
2
E
1
3
MA
1
4
VMM
1
5
GND
6
GND
7
Phase
1
8
CD
1
9
VR
1
10
C
1
11
V
CC
12
24
NC
23
MB
2
22
E
2
21
MA
2
22
21
20
19
18
M
B2
3
GND
2
GND
1
GND
28
GND
26
CD
2
4
M
A2
E
1 2
V
MM1 3
M
A1 4
GND
5
GND
6
Phase
1 7
CD
1 8
V
R1 9
C
1 10
V
CC 11
E
2
V
MM2
M
A2
GND
GND
Phase
2
CD
2
V
R2
C
2
RC
V
MM2 5
E
2 6
M
B2 7
27
Phase
2
25
V
R2
24
C
2
23
RC
NJM
3771E3
20
VMM
2
19
GND
18
GND
17
Phase
2
16
CD
2
15
NJM
3771D2
17
16
15
14
13
12
M
B1 8
GND
9
E
1 10
V
MM1 11
NJM 3771FM2
22
V
CC
21
C
1
20
V
R1
19
CD
1
VR
2
14
C
2
13
RC
M
A1 12
GND
13
GND
14
GND
15
GND
16
GND
17
Figure 2. Pin configurations
s
PIN DESCRIPTION
Refer to Figure 2
EMP
DIP
PLCC
Symbol
Description
2
3
4
5
6,7,
18,19
8
9
10
11
1
2
3
4
5,6,
17,18
7
8
9
10
8
10
11
12
1-3,9,
13-17,28
18
19
20
21
M
B1
E
1
V
MM1
M
A1
GND
Phase
1
CD
1
V
R1
C
1
12
13
14
11
12
13
22
23
24
V
CC
RC
C
2
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 to ground.
Motor supply voltage, channel 1, 10 to 40 V. V
MM1
and V
MM2
should be connected together.
Motor output A, channel 1. Motor current flows from M
A1
to M
B1
when Phase
1
is HIGH.
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.
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.
Current decay control, channel 1. A logic HIGH on this input results in
slow
current decay,
a LOW results in
fast
current decay, see “Functional Description.”
Reference voltage, channel 1. Controls the threshold voltage for the comparator and hence
the output current. Input resistance is typically 2.5 kohms,
±20%.
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
(0.450 / 2.5) • V
R1
, 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
(0.450 / 2.5) • V
R1
, i.e. 450 mV at V
R1
= 2.5 V.
Reference voltage, channel 2. Controls the threshold voltage for the comparator and hence
the output current. Input resistance is typically 2.5 kohms,
±20%.
Current decay control, channel 2. A logic HIGH on this input results in
slow
current decay,
a LOW results in
fast
current decay, see “Functional Description.”
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 output A, channel 2. 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.
Common emitter, channel 2. This pin connects to a sensing resistor to ground.
Motor output B, channel 2. Motor current flows from M
A2
to M
B2
when Phase
2
is HIGH.
15
16
17
20
21
22
23
14
15
16
19
20
21
22
25
26
27
4
5
6
7
V
R2
CD
2
Phase
2
M
A2
V
MM2
E
2
M
B2
Phase
1 18
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