A3969
Dual Full-Bridge PWM Motor Driver
Last Time Buy
This part is in production but has been determined to be
LAST TIME BUY. This classification indicates that the product is
obsolete and notice has been given. Sale of this device is currently
restricted to existing customer applications. The device should not be
purchased for new design applications because of obsolescence in the
near future. Samples are no longer available.
Date of status change: November 1, 2010
Deadline for receipt of LAST TIME BUY orders: April 30, 2011
Recommended Substitutions:
For existing customer transition, and for new customers or new appli-
cations, contact Allegro Sales.
NOTE: For detailed information on purchasing options, contact your
local Allegro field applications engineer or sales representative.
Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan
for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The
information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon-
sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
A3969
Dual Full-Bridge PWM Motor Driver
Features and Benefits
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±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 A3969 is designed to drive both windings of a two-phase
bipolar stepper motor. The 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.
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: 28 pin QFN (suffix ET)
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.
Continued on the next page…
Approximate scale
Typical Application
+3.3 V
+24 V
+3.3 V
20 kΩ
10 kΩ
56 kΩ
680 pF
47 μF
28
27
26
25
24
23
22
21
20
19
0.5 Ω
18
17
16
EN1
PH1
15
0.5 Ω
1
2
3
4
5
LOGIC
LOGIC
EN2
PH2
6
7
V
BB
10
12
13
DS3969, Rev. 2
14
11
8
9
A3969
Dual Full-Bridge PWM Motor Driver
and flyback diodes, and crossover-current protection.
The A3969 is supplied in a 28-pin QFN lead (Pb) free plastic package
with exposed thermal pad and 100% matte tin leadframe plating. It
has a 5 x 5 mm footprint and 0.90 mm nominal height.
Description (continued)
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
Selection Guide
Tape, 3000 pieces/reel
*Contact Allegro for additional packing options
Part Number
A3969SETTR-T
Packing*
Package
5 x 5 mm QFN, 28 pin
Absolute Maximum Ratings
Characteristic
Load Supply Voltage
Symbol
V
BB
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 a
junction temperature of 150°C.
Notes
Rating
30
±750
±650
7
-0.3 to
V
CC
+ 0.3
0.45
Range S
–20 to 85
150
–55 to 150
Units
V
mA
mA
V
V
V
ºC
ºC
ºC
Logic Supply Voltage
Input Voltage
Sense Voltage
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
V
CC
V
in
V
S
T
A
T
J
(max)
T
stg
Thermal Characteristics*
(additional data available on Allegro Web site)
Characteristic
Package Thermal Resistance, Junction-to-Ambient
Package Thermal Resistance, Junction-to-Tab
Package Power Dissipation
Symbol
R
θJA
R
θJT
P
D
(max)
R
θJA
= 32 °C/W, T
A
= 25°C
Notes
4-layer PCB, based on JEDEC standard
Rating
32
2
3.9
Units
°C/W
°C/W
W
* Per SEMI G42-88 Specification,
Thermal Test Board Standardization for Measuring Junction-to-Ambient Thermal Resistance of Semiconductor
Packages.
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
2
A3969
Dual Full-Bridge PWM Motor Driver
Functional Block Diagram
VCC
OUT 1A
OUT1B
OUT 2A
OUT 2B
VBB
PH1
V BB
PH2
UVLO
& TSD
CONTROL LOGIC1
CONTROL LOGIC2
UVLO
& TSD
EN1
CURRENT-SENSE
COMPARATOR
1
CURRENT-SENSE
COMPARATOR
2
EN2
SOURCE
ENABLE 1
PWM LATCH
1
R
Q
S
BLANKING
GATE
1
+
–
+
–
BLANKING
GATE
2
PWM LATCH
2
R
Q
S
÷4
OSC
SOURCE
ENABLE 2
GND
RC
SENSE
1
R1S
SENSE
2
R2S
REF
Dwg. FP-036-7
RT
CT
28 OUT2B
26 VCC
NC
SENSE2
1
2
3
4
5
6
7
NC 10
8
9
V
BB
22 VBB
21 OUT1B
20 NC
19 SENSE1
18 NC
17 GND
16 EN1
15 PH1
NC 14
24 REF
NC 12
Pin-out Diagram
NC
GND
NC
EN2
PH2
LOGIC
LOGIC
OUT1A 13
OUT2A
GND 11
NC
23 NC
27 NC
25 RC
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
3
A3969
Dual Full-Bridge PWM Motor Driver
ELECTRICAL CHARACTERISTICS at T
A
= +25°C, V
BB
= 30 V, V
CC
= 3.0 V to 3.6 V, V
REF
= 1.7 V,
V
S
= 0 V, 56 kΩ and 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
Source Driver, I
OUT
= -400 mA
Output Saturation Voltage
V
CE(SAT)
Source Driver, I
OUT
= -650 mA
Sink Driver, I
OUT
= +400 mA, V
S
= 0.425 V
Sink Driver, I
OUT
= +650 mA, V
S
= 0.425 V
Clamp Diode Forward Voltage
Motor Supply Current
(No Load)
V
F
I
BB(ON)
I
BB(OFF)
I
F
= 400 mA
I
F
= 650 mA
V
ENABLE1
= V
ENABLE2
= 0.8 V
V
ENABLE1
= V
ENABLE2
= 2.4 V
5
—
—
—
—
—
—
—
—
—
—
—
<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
μA
μA
V
V
V
V
V
V
mA
μA
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Control Logic
Logic Supply Voltage Range
Logic Input Voltage
Logic Input Current
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
CC
V
IN(1)
V
IN(0)
I
IN(1)
I
IN(0)
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
3.00
2.4
—
—
—
0.1
-2.5
3.8
-6.0
-0.3
12
—
—
—
<1.0
<-20
–
0
4.0
0
—
18
3.60
—
0.8
20
-200
1.7
1.0
4.2
6.0
0.425
24
V
V
V
μA
μA
V
μA
—
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, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
4
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