A3953
Full-Bridge PWM Motor Driver
Discontinued Product
This device is no longer in production. The device should not be
purchased for new design applications. Samples are no longer available.
Date of status change: January 30, 2012
Recommended Substitutions:
For existing customer transition, and for new customers or new appli-
cations, refer to the
A4973.
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.
A3953
Full-Bridge PWM Motor Driver
Features and Benefits
▪
±1.3 A continuous output current
▪
50 V output voltage rating
▪
3 V to 5.5 V logic supply voltage
▪
Internal PWM current control
▪
Saturated sink drivers (below 1 A)
▪
Fast and slow current-decay modes
▪
Automotive capable
▪
Sleep (low current consumption) mode
▪
Internal transient-suppression diodes
▪
Internal thermal shutdown circuitry
▪
Crossover current and UVLO protection
Description
Designed for bidirectional pulse width modulated (PWM)
current control of inductive loads, the A3953 is capable of
continuous output currents to ±1.3 A and operating voltages
to 50 V. Internal fixed off-time PWM current-control circuitry
can be used to regulate the maximum load current to a desired
value. The peak load current limit is set by the user’s selection
of an input reference voltage and external sensing resistor. The
fixed off-time pulse duration is set by a user- selected external
RC timing network. Internal circuit protection includes thermal
shutdown with hysteresis, transient-suppression diodes, and
crossover current protection. Special power-up sequencing is
not required.
With the ENABLE input held low, the PHASE input controls
load current polarity by selecting the appropriate source and
sink driver pair. The MODE input determines whether the
PWM current-control circuitry operates in a slow current-decay
mode (only the selected source driver switching) or in a fast
current-decay mode (selected source and sink switching). A
user-selectable blanking window prevents false triggering of
the PWM current-control circuitry. With the ENABLE input
held high, all output drivers are disabled. A sleep mode is
provided to reduce power consumption.
Continued on the next page…
Packages:
Package B, 16-pin DIP
with exposed tabs
Not to scale
Package LB, 16-pin SOIC
with internally fused pins
Functional Block Diagram
LOAD
SUPPLY
LOGIC
SUPPLY
6
V
CC
SLEEP &
STANDBY MODES
9
10
15
MODE
14
V
BB
PHASE
7
UVLO
& TSD
ENABLE
8
BRAKE
1
INPUT LOGIC
Q
BLANKING
S
GROUND
4
5
V
CC
RC
3
+ –
2
RT
CT
V TH
29319.8I
–
R
+
PWM LATCH
LOAD
SUPPLY
16
OUT A
OUT B
11
SENSE
RS
12
REF
13
GROUND
Dwg. FP-036-2A
A3953
Description (continued)
When a logic low is applied to the BRAKE input, the braking
function is enabled. This overrides ENABLE and PHASE to turn
off both source drivers and turn on both sink drivers. The brake
function can be used to dynamically brake brush DC motors.
The A3953 is supplied in a choice of two power packages; a
16-pin dual-in-line plastic package with copper heat-sink tabs,
Selection Guide
Part Number
A3953SB-T
A3953SLBTR-T
Package
16-pin DIP with exposed thermal tabs
16-pin SOICW with internally-fused pins
Full-Bridge PWM Motor Driver
and a 16-pin plastic SOIC with copper heat-sink tabs. For both
package styles, the power tab is at ground potential and needs no
electrical isolation. Each package type is available in a lead (Pb)
free version (100% matte tin plated leadframe).
Packing
25 pieces per tube
1000 pieces per reel
Absolute Maximum Ratings
Characteristic
Load Supply Voltage
Logic Supply Voltage
Logic/Reference Input Voltage Range
Sense Voltage
Symbol
V
BB
V
CC
V
IN
V
SENSE
V
CC
= 5.0 V
V
CC
= 3.3 V
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 tempera-
ture of 150°C.
Range S
Fault conditions that produce excessive junction temperature
will activate the device’s thermal shutdown circuitry. These
conditions can be tolerated but should be avoided.
Notes
Rating
50
7.0
–0.3 to V
CC
+ 0.3
1.0
0.4
±1.3
See graph
–20 to 85
150
–55 to 150
Units
V
V
V
V
V
A
W
ºC
ºC
ºC
Output Current, Continuous
Package Power Dissipation
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
I
OUT
P
D
T
A
T
J
(max)
T
stg
Thermal Characteristics
Characteristic
Package Thermal Resistance, Junction
to Ambient
Package Thermal Resistance, Junction
to Tab
Symbol
R
θJA
Test Conditions*
2
B Package, single-layer PCB, 1 in. 2-oz. exposed copper
2
LB Package, 2-layer PCB, 0.3 in. 2-oz. exposed copper each
side
Value
43
67
6
Units
ºC/W
ºC/W
ºC/W
R
θJT
*Additional thermal information available on Allegro website.
ALLOWABLE PACKAGE POWER DISSIPATION (W)
4
R
θJT
= 6.0°C/W
BRAKE
1
2
3
4
V
BB
16
15
14
13
LOAD
SUPPLY
OUTB
MODE
GROUND
GROUND
SENSE
OUTA
LOAD
SUPPLY
Note the A3953SB (DIP) and
the A3953SLB (SOIC) are
electrically identical and share
a common terminal number
assignment.
REF
RC
GROUND
GROUND
LOGIC
SUPPLY
PHASE
ENABLE
3
SUFFIX 'B', R
θJA
= 43°C/W
LOGIC
5
6
7
8
V
BB
V
CC
12
11
10
9
2
1
SUFFIX 'LB', R
θJA
= 67°C/W
0
25
50
75
100
TEMPERATURE IN °C
125
150
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A3953
Full-Bridge PWM Motor Driver
ELECTRICAL CHARACTERISTICS at T
J
= 25°C, V
BB
= 5 V to 50 V, V
CC
= 3.0 V to 5.5 V
(unless otherwise noted.)
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Power Outputs
Load Supply Voltage Range
Output Leakage Current
V
BB
I
CEX
Operating, I
OUT
= ±1.3 A, L = 3 mH
V
OUT
= V
BB
V
OUT
= 0 V
Sense Current Offset
Output Saturation Voltage
BRAKE = H
(Forward/Reverse Mode)
I
SO
V
CE(SAT)
I
SENSE
- I
OUT1
, I
OUT
= 850 mA,
V
SENSE
= 0 V, V
CC
= 5 V
V
SENSE
= 0.4 V, V
CC
= 3.0 V:
Source Driver, I
OUT
= -0.85 A
Source Driver, I
OUT
= -1.3 A
Sink Driver, I
OUT
= 0.85 A
Sink Driver, I
OUT
= 1.3 A
Output Saturation Voltage
BRAKE = L
(Brake Mode)
Clamp Diode Forward Voltage
(Sink or Source)
V
F
V
CE(SAT)
V
SENSE
= 0.4 V, V
CC
= 3.0 V:
Sink Driver, I
OUT
= 0.85 A
Sink Driver, I
OUT
= 1.3 A
I
F
= 0.85 A
I
F
= 1.3 A
—
—
—
—
1.0
1.3
1.2
1.4
1.2
1.5
1.4
1.6
V
V
V
V
—
—
—
—
1.0
1.7
0.4
1.1
1.1
1.9
0.5
1.3
V
V
V
V
V
CC
—
—
22
—
<1.0
<-1.0
33
50
50
-50
38
V
μA
μA
mA
Continued next page…
TRUTH TABLE
BRAKE
H
H
H
H
H
H
L
L
ENABLE
H
H
L
L
L
L
X
X
PHASE
X
X
H
H
L
L
X
X
MODE
H
L
H
L
H
L
H
L
OUT
A
Off
Off
H
H
L
L
L
L
OUT
B
Off
Off
L
L
H
H
L
L
Sleep Mode
Standby
Forward, Fast Current-Decay Mode
Forward, Slow Current-Decay Mode
Reverse, Fast Current-Decay Mode
Reverse, Slow Current-Decay Mode
Brake, Fast Current-Decay Mode
Brake, No Current Control
DESCRIPTION
X = Irrelevant
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
A3953
Full-Bridge PWM Motor Driver
ELECTRICAL CHARACTERISTICS (continued) at T
J
= 25°C, V
BB
= 5 V to 50 V, V
CC
= 3.0 V to
5.5 V (unless otherwise noted.)
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
AC Timing
PWM RC Fixed Off-time
PWM Turn-Off Time
t
OFF RC
t
PWM(OFF)
C
T
= 680 pF, R
T
= 30 kΩ, V
CC
= 3.3 V
Comparator Trip to Source Off,
I
OUT
= 25 mA
Comparator Trip to Source Off,
I
OUT
= 1.3 A
I
RC
Charge On to Source On,
I
OUT
= 25 mA
I
RC
Charge On to Source On,
I
OUT
= 1.3 A
V
CC
= 3.3 V, R
T
≥
12 kΩ, C
T
= 680 pF
V
CC
= 5.0 V, R
T
≥
12 kΩ, C
T
= 470 pF
Propagation Delay Times
t
pd
I
OUT
= ±1.3 A, 50% to 90%:
ENABLE On to Source On
ENABLE Off to Source Off
ENABLE On to Sink On
ENABLE Off to Sink Off (MODE = L)
PHASE Change to Sink On
PHASE Change to Sink Off
PHASE Change to Source On
PHASE Change to Source Off
Crossover Dead Time
Maximum PWM Frequency
t
CODT
f
PWM(max)
1 kΩ Load to 25 V, V
BB
= 50 V
I
OUT
= 1.3 A
—
—
—
—
—
—
—
—
0.3
70
1.0
1.0
1.0
0.8
2.4
0.8
2.0
1.7
1.5
—
—
—
—
—
—
—
—
—
3.0
—
μs
μs
μs
μs
μs
μs
μs
μs
μs
kHz
18.3
—
—
—
—
0.8
0.8
20.4
1.0
1.8
0.4
0.55
1.4
1.6
22.5
1.5
2.6
0.7
0.85
1.9
2.0
μs
μs
μs
μs
μs
μs
μs
PWM Turn-On Time
t
PWM(ON)
PWM Minimum On Time
t
ON(min)
Continued next page…
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
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