Approximate Scale 1:1
CPU
M
M
OUT1
IN4
IN3
A3901
+VBAT
OUT2
OUT3
OUT4
IN2
IN1
VBB
GND
10 F
10 V
CPU
M
OUT1
IN4
IN3
A3901
+VBAT
OUT2
OUT3
OUT4
IN2
IN1
VBB
GND
10 F
10 V
Figure 2. Typical dual dc motor control
Figure 3. Typical single dc motor control (paralleled outputs)
CPU
M
OUT1
IN4
IN3
A3901
+VBAT
OUT2
OUT3
OUT4
IN2
IN1
VBB
GND
10 F
10 V
Figure 1. Typical stepper motor control
A3901
Description
The A3901 is a dual full-bridge motor driver, designed for low
voltage portable applications involving bipolar stepper or brush
dc motors. The outputs have been optimized for low voltage
drop, with currents up to 400 mA (800 mA with outputs
paralleled) and an operating voltage range of 2.5 to 5.5 V.
The four inputs (IN1 to IN4) can control a bipolar stepper motor
in full- or half-step mode, or dc motors in forward, reverse, or
brake mode. The inputs can be PWMed for current or speed
control at frequencies up to 250 kHz.
Internal protection circuitry includes thermal shut down (TSD)
and crossover (shoot-through) protection.
The A3901 is supplied in a 3 x 3 x 0.75 mm nominal, 10-lead
DFN/MLP package, with exposed thermal pad (package "EJ").
This small footprint package is lead (Pb) free, with 100% matte
tin leadframe plating.
3901-DS
Features and Benefits
Low
R
DS(on)
outputs
Full- and half-stepping capability
Small
package
Forward, reverse, and brake modes for dc motors
Sleep mode with zero current drain
PWM control up to 250 kHz
Crossover-current
protection
Thermal shutdown (TSD)
Package: 10 Contact DFN/MLP (suffix EJ)
Typical Application
Dual Full Bridge Low Voltage Motor Driver
2
Dual Full Bridge Low Voltage Motor Driver
A3901
2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Parameter
Symbol
Conditions
Min.
Typ. Max. Units
Load Supply Voltage
V
BB
7
V
Output Current per Channel
*
I
OUT
400
mA
Logic Input Voltage Range
V
IN
0.3
6
V
Junction Temperature
T
J
150
C
Storage Temperature Range
T
S
40
150
C
Operating Temperature Range
T
A
20
85
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.
Selection Guide
Part Number
Packing
A3901SEJTR-T
Tape and reel, 1500 pieces/reel
Absolute Maximum Ratings
3
Dual Full Bridge Low Voltage Motor Driver
A3901
3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Control Logic
and Gate Drive
TSD
IN1
IN2
IN3
IN4
VBB
GND
OUT1
OUT2
BRIDGE1
BRIDGE2
OUT3
OUT4
PAD
10 F
10 V
Functional Block Diagram
10
9
8
7
6
OUT1
OUT2
VBB
PAD
OUT3
OUT4
1
2
3
4
5
IN1
IN2
GND
IN3
IN4
Terminal Diagram
Number
Name
Description
1
IN1
Logic input 1
2
IN2
Logic input 2
3
GND
Ground terminal
4
IN3
Logic input 3
5
IN4
Logic input 4
6
OUT4
Bridge2 output to load
7
OUT3
Bridge2 output to load
8
VBB
Load supply terminal
9
OUT2
Bridge1 output to load
10
OUT1
Bridge1 output to load
Pad
Exposed pad for thermal dissipation; connect to GND externally
4
Dual Full Bridge Low Voltage Motor Driver
A3901
4
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ELECTRICAL CHARACTERISTICS at T
A
=25C, and V
BB
= 2.5 to 5.5 V, unless noted otherwise
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max. Units
Output On Resistance
R
DS(on)
Source driver, V
BB
= 3 V, I
OUT
= 300 mA
1.8
2.1
Source driver, V
BB
= 5 V, I
OUT
= 300 mA
1.2
1.4
Sink driver, V
BB
= 3 V, I
OUT
= 300 mA
1.2
1.4
Sink driver, V
BB
= 5 V, I
OUT
= 300 mA
0.8
1.0
Clamp Diode
I = 300 mA
1.5
V
Motor Supply Current
I
BB
All outputs PWMed at 20 kHz
0.6
mA
Sleep mode, V
BB
= 3 V
100
nA
Sleep mode, V
BB
= 5 V
<50
500
nA
Logic Input Voltage
V
IN(1)
V
BB
/2
V
V
IN(0)
0.5
V
Logic Input Current
I
IN(1)
V
IN
= 2.0 V
<100
500
nA
I
IN(0)
V
IN
= 0.5 V
<100 500
nA
Input Voltage Hysteresis
V
hys
150
mV
Propagation Delay
t
pd(on)
Input Low to Sink On, Input High to Source On
130
ns
t
pd(off)
Input High to Sink Off, Input Low to Source Off
50
ns
Crossover Delay
t
COD
80
ns
Thermal Shut Down Temperature
T
J
150
C
Thermal Shut Down Hysteresis
T
Jhys
10
C
THERMAL CHARACTERISTICS
Characteristics
Symbol
Test Conditions
Rating
Unit
Package Thermal Resistance
*
R
JA
Measured on 4-layer board based on JEDEC
standard
45
C/W
Measured on 2-layer board with copper limited to
solder pads and 0.88 in
2
. of copper on each side
65
C/W
*
Additional thermal information is available on the Allegro Web site.
5
Dual Full Bridge Low Voltage Motor Driver
A3901
5
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Motor Operation Truth Table
INx
1
OUT1
2
OUT2
OUT3
OUT4
Function
Stepper Motor
IN1
IN2
IN3
IN4
Full Stepping
Half-Stepping
0
0
0
0
OFF
OFF
OFF
OFF
Sleep Mode
Sleep Mode
1
0
1
0
H
L
H
L
Step 1
Step 1
0
0
1
0
OFF
OFF
H
L
Step 2
0
1
1
0
L
H
H
L
Step 2
Step 3
0
1
0
0
L
H
OFF
OFF
Step 4
0
1
0
1
L
H
L
H
Step 3
Step 5
0
0
0
1
OFF
OFF
L
H
Step 6
1
0
0
1
H
L
L
H
Step 4
Step 7
1
0
0
0
H
L
OFF
OFF
Step 8
DC Motor (Dual)
IN1 or IN3
IN2 or IN4
0
0
OFF
OFF
OFF
OFF
Hi-Z (Sleep Mode)/Coast
1
0
H
L
H
L
Forward
0
1
L
H
L
H
Reverse
1
1
L
L
L
L
Brake
DC Motor (Single, Paralleled)
IN1 and IN3
IN2 and IN4
0
0
OFF
OFF
OFF
OFF
Hi-Z (Sleep Mode)/Coast
1
0
H
L
H
L
Forward
0
1
L
H
L
H
Reverse
1
1
L
L
L
L
Brake
DC Motor (External PWM)
IN1 or IN3
IN2 or IN4
1
0
0
0
H
OFF
L
OFF
H
OFF
L
OFF
Forward
Fast Decay
0
0
1
0
L
OFF
H
OFF
L
OFF
H
OFF
Reverse
Fast Decay
1
1
0
1
H
L
L
L
H
L
L
L
Forward
Slow Decay
0
1
1
1
L
L
H
L
L
L
H
L
Reverse
Slow Decay
1
0 = logic low, V
INx
< V
IN(0)(max)
; 1 = logic high, V
INx
> V
IN(1)(min)
2
H = voltage high, source driver on; L = voltage low, sink driver on
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