3961
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
3961
Designed for pulse-width modulated (PWM) current control of
bipolar stepper motors, the A3961S鈥?is capable of continuous output
currents to
鹵800
mA and operating voltages to 45 V. Internal fixed
off-time PWM current-control circuitry can be used to regulate the
maximum load current to a desired value. An internal precision voltage
reference is provided to improve motor peak current control accuracy.
The peak load current limit is set by the user鈥檚 selection of an external
resistor divider and current-sensing resistors.
The fixed off-time pulse duration is set by user-selected external
RC timing networks. The capacitor in the RC timing network also
determines a user-selectable blanking window that prevents false
triggering of the PWM current control circuitry during switching transi-
tions. This eliminates the need for two external RC filter networks on
the current-sensing comparator inputs.
Data Sheet
29319.26
DUAL FULL-BRIDGE PWM MOTOR DRIVER
OUT
1
1B
E
1
2
24
23
OUT
2B
E
2
Note the A3961SB (DIP) and the A3961SLB
(SOIC) are electrically identical and share a
common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, V
BB
. . . . . . . . . .
45 V
Output Current, I
OUT
. . . . . . . . . .
鹵
800 mA*
Logic Supply Voltage, V
CC
. . . . . . . . .
7.0 V
Logic Input Voltage Range,
V
IN
. . . . . . . . . . .
-0.3 V to V
CC
+ 0.3 V
Sense Voltage, V
SENSE
. . . . . . . . . . . .
1.0 V
Reference Output Current,
I
REF OUT
. . . . . . . . . . . . . . . . . . .
1.0 mA
Package Power Dissipation,
P
D
. . . . . . . . . . . . . . . . . . . .
See Graph
Operating Temperature Range,
T
A
. . . . . . . . . . . . . . . . .
-20藲C to +85藲C
Junction Temperature, T
J
. . . . . . .
+150藲C鈥?/div>
Storage Temperature Range,
T
S
. . . . . . . . . . . . . . . .
-55藲C to +150藲C
* Output current rating may be limited by duty
cycle, ambient temperature, and heat sinking.
Under any set of conditions, do not exceed the
specified current rating or a junction tempera-
ture of 150藲C.
鈥?Fault conditions that produce excessive
junction temperature will activate device
thermal shutdown circuitry. These conditions
can be tolerated but should be avoided.
T
C
U Y
D L
O N
R O
P E
D C
E N
U E
IN ER
T F
N E
O R
C R
IS O
D F
鈥?/div>
SENSE
1
3
OUT
1A
4
V
BB1
5
22
SENSE
2
21
OUT
2A
V
BB2
20
GROUND
6
19
GROUND
GROUND
7
V
REF
OUT
8
V
REF
IN
9
18
GROUND
17
I
FULL/PD
16
V
CC
RC
1
10
15
RC
2
PHASE
1
11
14
PHASE
2
ENABLE
1
12
13
ENABLE
2
For each bridge the PHASE input controls load current polarity by
selecting the appropriate source and sink driver pair. For each bridge
the ENABLE input, when held high, disables the output drivers. Special
power-up sequencing is not required. Internal circuit protection includes
thermal shutdown with hysteresis, transient-suppression diodes, and
crossover-current protection.
The A3961S鈥?is supplied in a choice of two power packages:
24-pin dual-in-line plastic package with copper heat-sink tabs and
24-lead plastic SOIC with copper heat-sink tabs. In both packages the
power tab is at ground potential and needs no electrical isolation.
FEATURES
s
s
s
s
s
s
s
鹵800
mA Continuous Output Current Rating
45 V Output Voltage Rating
Internal PWM Current Control, Saturated Sink Drivers
Internally Generated Precision 2.5 V Reference
Internal Transient-Suppression Diodes
Internal Thermal-Shutdown Circuitry
Crossover-Current Protection, UVLO Protection
Always order by complete part number:
PART NUMBER
A3961SB
A3961SLB
PACKAGE
24-Pin DIP
24-Lead SOIC
R
胃JA
40擄C/W
55擄C/W
R
胃JT
6擄C/W
6擄C/W
1
2
3
4
5
6
7
8
9
10
