A3966
Dual Full-Bridge PWM Motor Driver
Features and Benefits
▪
±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 and flyback diodes
▪
Internal thermal-shutdown circuitry
▪
Crossover-current protection and UVLO protection
Description
The A3966 is designed to drive both windings of a two-phase
bipolar stepper motor. The device includes two full-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 user selection of a reference voltage and current-sensing
resistors.
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.
Package: 16 pin SOICW (suffix LB)
To reduce on-chip power dissipation, the full-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
Not to scale
Continued on the next page…
Typical Application
1
PHASE
1
ENABLE
1
2
3
4
0.5
Ω
+5 V
6
5
LOGIC
LOGIC
V
BB
16
15
14
13
12
11
V
BB
PHASE
2
ENABLE
2
0.5
Ω
39 kΩ
+24 V
7
8
V
REF
V
CC
RC
10
9
+5 V
10 kΩ
Dwg. EP-047-4A
29319.25K
56 kΩ
47
μF
680 pF
+
A3966
Description (continued)
Dual Full-Bridge PWM Motor Driver
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 A3966 is supplied in a 16-lead plastic wide SOIC with two pins
internally fused to the die pad for enhanced thermal dissipation. These
pins are at ground potential and need no electrical isolation. The
device is lead (Pb) free, with 100% matte tin leadframe plating.
Selection Guide
Part Number
A3966SLBTR–T
Packing
1000 pieces / reel
Ambient Temperature Range
(°C)
–20 to 85
Absolute Maximum Ratings
Characteristic
Load Supply Voltage
Logic Supply Voltage
Input Voltage
Sense Voltage
Symbol
V
BB
V
CC
V
IN
V
S
Peak
Output Current*
I
OUT
Continuous
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 T
J
(max)
Notes
Rating
30
7.0
–0.3 to V
CC
+ 0.3
1.0
±750
±650
Units
V
V
V
V
mA
mA
Package Power Dissipation
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
P
D
T
A
T
J
(max)
T
stg
T
A
= 25°C; per SEMI G42-88 Specification, Thermal Test
Board Standardization for Measuring Junction-to-Ambient
Thermal Resistance of Semiconductor Packages.
Range S
1.87
–20 to 85
150
–55 to 150
W
ºC
ºC
ºC
Pin-out Diagram
OUT
1A
PHASE
1
ENABLE
1
GROUND
SENSE
1
OUT
1B
LOAD
SUPPLY
REFERENCE
1
2
3
4
5
6
V
7
8
V
BB
16
V
BB
OUT
2A
PHASE
2
ENABLE
2
GROUND
SENSE
2
OUT
2B
LOGIC
SUPPLY
RC
15
14
LOGIC
LOGIC
13
12
11
V
CC
10
9
REF
RC
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A3966
Dual Full-Bridge PWM Motor Driver
FUNCTIONAL BLOCK DIAGRAM
OUT 1A
OUT 1B
V CC
PHASE
1
V BB
PHASE 2
+
LOGIC
SUPPLY
OUT 2A
OUT 2B
LOAD
SUPPLY
UVLO
& TSD
CONTROL LOGIC1
CONTROL LOGIC2
UVLO
& TSD
ENABLE
1
SOURCE
ENABLE 1
ENABLE 2
CURRENT-SENSE
COMPARATOR
1
SENSE
1
SENSE
2
CURRENT-SENSE
COMPARATOR
2
PWM LATCH
1
R
Q
S
BLANKING
GATE
1
+
–
+
–
BLANKING
GATE
2
PWM LATCH
2
R
Q
S
÷4
OSC
RC
R1S
R 2S
SOURCE
ENABLE 2
GROUND
RT
CT
REFERENCE
Dwg. FP-036-6
TRUTH TABLE
PHASE
X
H
L
ENABLE
H
L
L
OUT
A
Off
H
L
OUT
B
Off
L
H
2.5
OUTPUT SATURATION VOLTAGE IN VOLTS
T
A
= +25°C
2.0
SOURCE DRIVER
1.5
X = Irrelevant
1.0
Typical output saturation voltages showing
Satlington sink-driver operation.
0.5
SINK DRIVER
0
200
300
400
500
600
7 00
Dwg. GP-064-1A
OUTPUT CURRENT IN MILLIAMPERES
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
A3966
Dual Full-Bridge PWM Motor Driver
ELECTRICAL CHARACTERISTICS at T
A
= +25 C, V
BB
= 30 V, V
CC
= 4.75 V to 5.5 V, V
REF
= 2 V,
V
S
= 0 V, 56 k & 680 pF RC to Ground (unless noted otherwise)
Limits
Characteristic
Output Drivers
Load Supply Voltage Range
Output Leakage Current
V
BB
I
CEX
Operating, I
OUT
= 650 mA, L = 3 mH
V
OUT
= 30 V
V
OUT
= 0 V
Output Saturation Voltage
V
CE(SAT)
Source Driver, I
OUT
= -400 mA
Source Driver, I
OUT
= -650 mA
Sink Driver, I
OUT
= +400 mA, V
S
= 0.5 V
Sink Driver, I
OUT
= +650 mA, V
S
= 0.5 V
Clamp Diode Forward Voltage
V
F
I
F
= 4 0 0 m A
I
F
= 6 5 0 m A
Motor Supply Current
(No Load)
I
BB(ON)
I
BB(OFF)
V
ENABLE1
= V
ENABLE2
= 0.8 V
V
ENABLE1
= V
ENABLE2
= 2.4 V
V
CC
—
—
—
—
—
—
—
—
—
—
—
<1.0
<-1.0
1.7
1.8
0.3
0.7
1.1
1.4
3.0
<1.0
30
50
-50
2.0
2.1
0.5
1.3
1.4
1.6
5.0
200
V
A
A
V
V
V
V
V
V
mA
A
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Control Logic
Logic Supply Voltage Range
Logic Input Voltage
V
CC
V
IN(1)
V
IN(0)
Logic Input Current
I
IN(1)
I
IN(0)
Reference Input Volt. Range
Reference Input Current
Reference Divider Ratio
Current-Sense Comparator
Input Offset Voltage
Current-Sense Comparator
Input Voltage Range
Sense-Current Offset
V
REF
I
REF
V
REF
/V
TRIP
V
IO
V
S
I
SO
V
REF
= 0 V
Operating
I
S
– I
OUT
, 50 mA
I
OUT
650 mA
V
IN
= 2.4 V
V
IN
= 0.8 V
Operating
Operating
4.75
2.4
—
—
—
0.1
-2.5
3.8
-6.0
-0.3
12
—
—
—
<1.0
<-20
–
0
4.0
0
—
18
5.50
—
0.8
20
-200
2.0
1.0
4.2
6.0
1.0
24
V
V
V
A
A
V
A
—
mV
V
mA
NOTES:1. Typical Data is for design information only.
2. Negative current is defined as coming out of (sourcing) the specified device terminal.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
A3966
Dual Full-Bridge PWM Motor Driver
ELECTRICAL CHARACTERISTICS at T
A
= +25 C, V
BB
= 30 V, V
CC
= 4.75 V to 5.5 V, V
REF
= 2 V,
V
S
= 0 V, 56 k & 680 pF RC to Ground (unless noted otherwise) (cont.)
Limits
Characteristic
Control Logic
(continued)
PWM RC Frequency
PWM Propagation Delay Time
f
osc
t
PWM
C
T
= 680 pF, R
T
= 56 k
Comparator Trip to Source OFF
Cycle Reset to Source ON
Cross-Over Dead Time
Propagation Delay Times
t
codt
t
pd
1k
Load to 25 V
22.9
—
—
0.2
—
—
—
—
—
—
—
—
—
—
Increasing V
CC
—
0.1
V
ENABLE 1
= V
ENABLE 2
= 0.8 V
V
ENABLE 1
= V
ENABLE 2
= 2.4 V
—
—
25.4
1.0
0.8
1.8
100
500
200
200
2200
200
2200
200
165
15
4.1
0.6
—
—
27.9
1.4
1.2
3.0
—
—
—
—
—
—
—
—
—
—
4.6
—
50
9.0
kHz
s
s
s
ns
ns
ns
ns
ns
ns
ns
ns
C
C
V
V
mA
mA
Symbol
Test Conditions
Min.
Typ.
Max.
Units
I
OUT
= 650 mA, 50% to 90%:
ENABLE ON to Source ON
ENABLE OFF to Source OFF
ENABLE ON to Sink ON
ENABLE OFF to Sink OFF
PHASE Change to Sink ON
PHASE Change to Sink OFF
PHASE Change to Source ON
PHASE Change to Source OFF
Thermal Shutdown Temp.
Thermal Shutdown Hysteresis
UVLO Enable Threshold
UVLO Hysteresis
Logic Supply Current
T
J
T
J
V
T(UVLO)+
V
T(UVLO)hys
I
CC(ON)
I
CC(OFF)
NOTES:1. Typical Data is for design information only.
2. Negative current is defined as coming out of (sourcing) the specified device terminal.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
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