Document
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
PACKAGE: 16-pin SOICW (suffix LB)
Not to scale
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.
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 each bridge, an ENABLE input, when held high, disables
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Typical Application
29319.25K, Rev. 13 MCO-0000728
PHASE 1 ENABLE1
+5 V
0.5 Ω +24 V
39 kΩ
47 µF
+
1
16
2
V BB
15
3
14
4
LOGIC LOGIC
13
5
12
6 V BB
7
8 VREF
11 VCC 10
RC 9
PHASE 2 ENABLE2 0.5 Ω
+5 V
10 kΩ
Dwg. EP-047-4A
56 kΩ 680 pF
October 25, 2021
A3966
Dual Full-Bridge PWM Motor Driver
DESCRIPTION (CONTINUED) 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
Symbol
Load Supply Voltage
VBB
Logic Supply Voltage
VCC
Input Voltage
VIN
Sense Voltage
VS
Output Current*
IOUT
Package Power Dissipation
Operating Ambient Temperature Maximum Junction Temperature Storage Temperature
PD
TA TJ(max)
Tstg
Notes
Peak 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 TJ(max)
TA = 25°C; per SEMI G42-88 Specification, Thermal Test Board Standardization for Measuring Junction-to-Ambient
Thermal Resistance of Semiconductor Packages.
Range S
Rating 30 7.0
–0.3 to VCC + 0.3 1.0 ±750
±650
1.87
–20 to 85 150
–55 to 150
Units V V V V mA
mA
W
°C °C °C
PINOUT DIAGRAM
OUT1A 1 PHASE 1 2 ENABLE 1 3 GROUND 4
V BB LOGIC LOGIC
16 OUT2A 15 PHASE 2 14 ENABLE 2 13 GROUND
SENSE1 5
OUT1B 6
LOAD SUPPLY
7
V BB
REFERENCE 8 VREF
12 SENSE 2
11 OUT 2B
VCC
10
LOGIC SUPPLY
RC 9 RC
Dwg. PP-066-1
2
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
A3966
Dual Full-Bridge PWM Motor Driver
FUNCTIONAL BLOCK DIAGRAM
OUT 2A OUT 2B +
OUT 1A OUT1B
PHASE 1
LOGIC SUPPLY
V CC
V BB
LOAD SUPPLY
CONTROL LOGIC1
UVLO & TSD
ENABLE 1 RT
SOURCE ENABLE 1
BLANKING
PWM LATCH 1
GATE 1
R
Q S
CURRENT-SENSE
COMPARATOR 1
+ –
RC
CT
OSC
SENSE 1
R1S
SENSE 2
R 2S
CURRENT-SENSE
COMPARATOR 2
+ –
BLANKING
GATE 2
PWM LATCH 2
R
Q S
÷4
REFERENCE
CONTROL LOGIC2
SOURCE ENABLE 2
PHASE2 UVLO & TSD
ENABLE 2
GROUND
Dwg. FP-036-6
TRUTH TABLE
PHASE X H L
ENABLE H L L
OUTA Off
H
L
OUTB Off
L
H
X = Irrelevant
Typical output saturation voltages showing Satlington sink-driver operation.
OUTPUT SATURATION VOLTAGE IN VOLTS
2.5 TA = +25°C
2.0
1.5
1.0
SOURCE DRIVER
0.5 SINK DRIVER
0
200
300
400
500
600
700
OUTPUT CURRENT IN MILLIAMPERES
Dwg. GP-064-1A
3
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
A3966
Dual Full-Bridge PWM Motor Driver
EVSLE=C0TVR,IC56AkLC&HA6R80ACpFTERRCIStoTIGCrSoautnTdA(=un+l2e5sosCn, oVtBeBd=o3th0eVrw, VisCeC) = 4.75 V to 5.5 V, VREF = 2 V,
Characteristic Output Drivers
Symbol Test Conditions
Min.
Limits Typ. Max.
Units
Load Supply Voltage Range
VBB
Operating, IOUT = p650 mA.