SLUS403A - FEBRUARY 2000
BLOCK DIAGRAM
Full-Step, Half-Step and Micro-Step
Capability.
Bipolar Output Current up to 2A.
Wide Range of Motor Supply Voltage:
1050V
Low Saturation Voltage
Wide Range of Current Control: 5mA2A.
Current Levels Selected in Steps or Varied
Continuously.
Thermal Protection and Soft Intervention.
The UC3770A and UC3770B are high-performance full bridge driv-
ers that offer higher current and lower saturation voltage than the
UC3717 and the UC3770. Included in these devices are LS-TTL
compatible logic inputs, current sense, monostable, thermal shut-
down, and a power H-bridge output stage. Two UC3770As or
UC3770Bs and a few external components form a complete micro-
processor-controllable stepper motor power system.
Unlike the UC3717, the UC3770A and the UC3770B require exter-
nal high-side clamp diodes.
The UC3770A and UC3770B are
identical in all regards except for the current sense thresholds.
Thresholds for the UC3770A are identical to those of the older
UC3717 permitting drop-in replacement in applications where
high-side diodes are not required. Thresholds for the UC3770B are
tailored for half stepping applications where 50%, 71%, and 100%
current levels are desirable.
The UC3770A and UC3770B are specified for operation from 0
C
to 70
C ambient.
UC3770A
UC3770B
High Performance Stepper Motor Drive Circuit
FEATURES
DESCRIPTION
UDG-92039-1
2
CONNECTION DIAGRAMS
UC3770A
UC3770B
UC3770A
UC3770B
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Supply Voltage V
M
(Pins 3, 14)
10
45
10
45
V
Logic Supply Voltage V
CC
(Pin 6)
4.75
5
5.3
4.75
5
5.3
V
Logic Supply Current I
CC
(Pin 6)
I
O
= I
1
= H, I
M
= 0
15
25
15
25
mA
I
O
= I
1
= L, I
M
= 0
18
28
18
28
mA
I
O
= I
1
= H, I
M
= 1.3A
33
40
33
40
mA
Thermal Shutdown Temperature
+170
+170
C
Logic Threshold (Pins 7, 8, 9)
0.8
2.0
0.8
2.0
V
Input Current Low (Pin 8)
V
I
= 0.4V
-100
-100
A
Input Current Low (Pins 7, 9)
V
I
= 0.4V
-400
-400
A
Input Current High (Pins 7, 8, 9)
V
I
= 2.4V
10
10
A
Comparator Threshold (Pin 10)
V
R
= 5V, I
0
= L, I
1
= L
400
415
430
400
415
430
mV
V
R
= 5V, I
0
= H, I
1
= L
240
255
265
290
300
315
mV
V
R
= 5V, I
0
= L, I
1
= H
70
80
90
195
210
225
mV
Comparator Input Current (Pin 10)
20
20
A
Off Time
R
T
= 56k, C
T
= 820pF
25
30
35
25
30
35
ms
PACKAGE PIN FUNCTION
FUNCTION
PIN
Gnd
1-3
V
M
4
N/C
5
A
OUT
6
N/C
7
Emitters
8
Gnd
9
B
OUT
10
Timing
11
V
M
12
Gnd
13-17
V
CC
18
I
1
19
Phase
20
I
0
21
N/C
22
Current
23
V
R
24
N/C
25-27
Gnd
28
PLCC-28 (Top View)
Q Package
DIL-16 (Top View)
J Or N Package
Logic Supply Voltage, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Output Supply Voltage, VMM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50V
Logic Input Voltage (Pins 7, 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V
Analog Input Voltage (Pin 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
CC
Reference Input Voltage (Pin 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V
Logic Input Current (Pins 7, 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Analog Input Current (Pins 10, 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Output Current (Pins 1, 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2A
Junction Temperature, T
J
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150
C
ABSOLUTE MAXIMUM RATINGS
Note 1: All voltages are with respect to Gnd (DIL Pins 4, 5, 12, 13); all currents
are positive into, negative out of the specified terminal.
Note 2: Consult Unitrode Integrated Circuits databook for thermal limitations and
considerations of packages.
ELECTRICAL CHARACTERISTICS: (All tests apply with V
M
= 36V, V
CC
= 5V, V
R
= 5V, No Load, and 0
C<T
A
<70
C, unless
otherwise stated, T
A
= T
J
.)
3
UNITRODE CORPORATION
7 CONTINENTAL BLVD. MERRIMACK, NH 03054
TEL. 603-424-2410 FAX 603-424-3460
UC3770A
UC3770B
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Turn Off Delay
2
2
ms
Sink Driver Saturation Voltage
I
M
= 1.0A
0.8
0.8
V
I
M
= 1.3A
1.3
1.3
V
Source Driver Saturation Voltage
I
M
= 1.0A
1.3
1.3
V
I
M
= 1.3A
1.6
1.6
V
Output Leakage Current
V
M
= 45V
100
100
A
UC3770A
UC3770B
ELECTRICAL CHARACTERISTICS (cont.): (All tests apply with V
M
= 36V, V
CC
= 5V, V
R
= 5V, No Load, and 0
C<T
A
<70
C,
unless otherwise stated, T
A
= T
J
.)
0
1
2
3
4
5
0
0.5
1
1.5
2
OUTPUT CURRENT (A)
PO
WER
D
ISSIP
A
TION
(W)
Figure 4. Typical power dissipation vs. output
current.
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0.2
2.5
3.0
3.5
4.0
4.5
5.0
T
A
= +25C
OUTPUT CURRENT A
I
CC
mA
Figure 3. Typical supply current vs. load current.
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0.6
0.8
1.0
1.2
1.4
1.6
1.8
T
A
= +25C
OUTPUT CURRENT A
V
CE
SAT
HIGH
V
Figure 1. Typical source saturation voltages vs. load
current
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
T
A
= +25C
OUTPUT CURRENT A
V
CE
SAT
LOW
V
Figure 2. Typical sink saturation voltages vs. load
current
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