3966
A3966SLB
(SOIC)
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-frequency, 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 the Allegro
®
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. The A3966SLB
is also available in a lead (Pb) free version, with 100% matte tin leadframe plating.
Data Sheet
29319.25G
OUT
1A
PHASE
1
ENABLE
1
GROUND
SENSE
1
OUT
1B
LOAD
SUPPLY
REFERENCE
1
2
3
4
5
6
V
7
8
V
REF
BB
16
V
BB
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
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
■
■
■
■
■
■
■
■
±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
P a rt N um b e r
A 3 9 6 6 S L B -T
A 3 9 6 6 S L B T R -T
*
P b -fre e *
Ye s
Ye s
P ackage
1 6 -L e a d S O IC
1 6 -L e a d S O IC
P a c k ing
4 7 p e r tub e
1 0 0 0 p e r re e l
Pb-based variants are being phased out of the product line. The variants cited in this
footnote are in production but have been determined to be LAST TIME BUY. This
classification indicates that sale of this device is currently restricted to existing customer
applications. The variants should not be purchased for new design applications because
obsolescence in the near future is probable. Samples are no longer available. Status
change: October 31, 2006. Deadline for receipt fo LAST TIME BUY orders: April 27, 2007.
These variants include: A3966SA, A3966SLB, and A3966SLBTR.
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
