Data Sheet
29319.25A†
3966
A3966SLB
OUT
1A
PHASE
1
ENABLE
1
GROUND
SENSE
1
OUT
1B
LOAD
SUPPLY
REFERENCE
1
V
2
3
4
5
6
V
7
8
V
BB
BB
DUAL FULL-BRIDGE PWM
MOTOR DRIVER
The A3966SA and A3966SLB are designed to drive both windings of a
two-phase bipolar stepper motor. Each device includes two H-bridges
capable of continuous output currents of
±650
mA and operating voltages to
30 V. Motor winding current can be controlled by the internal fixed-fre-
quency, pulse-width modulated (PWM), current-control circuitry. The peak
load current limit is set by the user’s selection of a reference voltage and
current-sensing resistors. Except for package style and pinout, the two
devices are identical.
The fixed-frequency pulse duration is set by a user-selected external
RC timing network. 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 transitions.
To reduce on-chip power dissipation, the H-bridge power outputs have
been optimized for low saturation voltages. The sink drivers feature Allegro’s
patented Satlington™ output structure. The Satlington outputs combine the
low voltage drop of a saturated transistor and the high peak current capability
of a Darlington.
For each bridge, a PHASE input controls load-current polarity by
selecting the appropriate source and sink driver pair. For each bridge, an
ENABLE input, when held high, disables the output drivers. Special power-
up sequencing is not required. Internal circuit protection includes thermal
shutdown with hysteresis, ground-clamp and flyback diodes, and crossover-
current protection.
The A3966SA is supplied in a 16-pin dual in-line plastic package. The
A3966SLB is supplied in a 16-lead plastic SOIC with copper heat sink tabs.
The power tab is at ground potential and needs no electrical isolation.
16
15
14
LOGIC
LOGIC
13
12
11
V
CC
RC
10
9
OUT
2A
PHASE
2
ENABLE
2
GROUND
SENSE
2
OUT
2B
LOGIC
SUPPLY
RC
REF
Dwg. PP-066-1
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, V
BB
......................
30 V
Output Current, I
OUT
(peak) ...........
±
750 mA
(continuous) ..............................
±
650 mA
Logic Supply Voltage, V
CC
....................
7.0 V
Input Voltage, V
in
........
-0.3 V to V
CC
+ 0.3 V
Sense Voltage, V
S
................................
1.0 V
Package Power Dissipation (T
A
= 25°C), P
D
A3966SA .....................................
2.08 W*
A3966SLB ...................................
1.87 W*
Operating Temperature Range,
T
A
.....................................
-20
°
C to +85
°
C
Junction Temperature,
T
J
..................................................
+150
°
C
Storage Temperature Range,
T
S
...................................
-55
°
C to +150
°
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 temperature of 150°C.
* Per SEMI G42-88 Specification,
Thermal Test Board
Standardization for Measuring Junction-to-Ambient
Thermal Resistance of Semiconductor Packages.
FEATURES
I
I
I
I
I
I
I
I
±650
mA Continuous Output Current
30 V Output Voltage Rating
Internal Fixed-Frequency PWM Current Control
Satlington™ Sink Drivers
User-Selectable Blanking Window
Internal Ground-Clamp & Flyback Diodes
Internal Thermal-Shutdown Circuitry
Crossover-Current Protection and UVLO Protection
Always order by complete part number:
Part Number
A3966SA
A3966SLB
Package
16-pin DIP
16-lead batwing SOIC
R
θJA
60°C/W
67°C/W
R
θJC
38°C/W
—
R
θJT
—
6°C/W
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
