Part Number
Package
R
JA
R
JT
A3953SB
16-Pin DIP
43
C/W
6
C/W
A3953SLB
16-Lead SOIC
67
C/W
6
C/W
FULL-BRIDGE PWM MOTOR DRIVER
Always order by complete part number:
Note the A3953SB (DIP) and the A3953SLB
(SOIC) are electrically identical and share a
common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, V
BB
. . . . . . . . . . 50 V
Output Current, I
OUT
(Continuous) . . . . . . . . . . . . . .
1.3 A*
Logic Supply Voltage, V
CC
. . . . . . . . . 7.0 V
Logic/Reference Input Voltage Range,
V
IN
. . . . . . . . . . . -0.3 V to V
CC
+ 0.3 V
Sense Voltage, V
SENSE
(V
CC
= 5.0 V) . . . . . . . . . . . . . . . . 1.0 V
(V
CC
= 3.3 V) . . . . . . . . . . . . . . . . 0.4 V
Package Power Dissipation,
P
D
. . . . . . . . . . . . . . . . . . . . See Graph
Operating Temperature Range,
T
A
. . . . . . . . . . . . . . . . . -20C to +85C
Junction Temperature, T
J
. . . . . . . +150C
Storage Temperature Range,
T
S
. . . . . . . . . . . . . . . . -55C to +150C
* 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 150C.
Fault conditions that produce excessive junction
temperature will activate the device's thermal
shutdown circuitry. These conditions can be
tolerated but should be avoided.
Designed for bidirectional pulse-width modulated (PWM) current control
of inductive loads, the A3953S-- 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.
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 A3953S-- is supplied in a choice of two power packages; a 16-pin
dual-in-line plastic package with copper heat-sink tabs, and a 16-lead plastic
SOIC with copper heat-sink tabs. For both package styles, the power tab is at
ground potential and needs no electrical isolation.
FEATURES
I 1.3 A Continuous Output Current
I 50 V Output Voltage Rating
I 3 V to 5.5 V Logic Supply Voltage
I Internal PWM Current Control
I Saturated Sink Drivers (Below 1 A)
I Fast and Slow Current-Decay Modes
I Automotive Capable
I Sleep (Low Current
Consumption) Mode
I Internal Transient-
Suppression Diodes
I Internal Thermal-
Shutdown Circuitry
I Crossover-Current
and UVLO Protection
Data Sheet
29319.8*
3953
MODE
GROUND
GROUND
LOGIC
SUPPLY
PHASE
GROUND
GROUND
RC
SENSE
LOAD
SUPPLY
Dwg. PP-056
BRAKE
REF
LOAD
SUPPLY
V
CC
OUTB
OUTA
V
BB
V
BB
LOGIC
ENABLE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
3953
FULL-BRIDGE
PWM MOTOR DRIVER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2
X = Irrelevant
FUNCTIONAL BLOCK DIAGRAM
V
BB
RC
V
CC
LOGIC
SUPPLY
LOAD
SUPPLY
9
PHASE
UVLO
& TSD
R S
Dwg. FP-036-2A
MODE
REF
OUT
A
OUT
B
ENABLE
SENSE
+
BRAKE
INPUT LOGIC
GROUND
Q
R
S
PWM LATCH
V
CC
+
BLANKING
SLEEP &
STANDBY MODES
VTH
R T
C T
1
2
3
6
7
8
10
11
14
15
4
GROUND
12
LOAD
SUPPLY
16
5
13
TRUTH TABLE
BRAKE
ENABLE
PHASE
MODE
OUT
A
OUT
B
DESCRIPTION
H
H
X
H
Off
Off
Sleep Mode
H
H
X
L
Off
Off
Standby
H
L
H
H
H
L
Forward, Fast Current-Decay Mode
H
L
H
L
H
L
Forward, Slow Current-Decay Mode
H
L
L
H
L
H
Reverse, Fast Current-Decay Mode
H
L
L
L
L
H
Reverse, Slow Current-Decay Mode
L
X
X
H
L
L
Brake, Fast Current-Decay Mode
L
X
X
L
L
L
Brake, No Current Control
Copyright 1995, 2000 Allegro MicroSystems, Inc.
3953
FULL-BRIDGE
PWM MOTOR DRIVER
www.allegromicro.com
3
50
75
100
125
150
5
1
0
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
TEMPERATURE IN
C
4
3
2
25
Dwg. GP-049-2A
R = 6.0
C/W
JT
SUFFIX 'B', R = 43
C/W
JA
SUFFIX 'LB', R = 63
C/W
JA
ELECTRICAL CHARACTERISTICS at T
J
= 25C, 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
Load Supply Voltage Range
V
BB
Operating, I
OUT
=
1.3 A, L = 3 mH
V
CC
--
50
V
Output Leakage Current
I
CEX
V
OUT
= V
BB
--
<1.0
50
A
V
OUT
= 0 V
--
<-1.0
-50
A
Sense Current Offset
I
SO
I
SENSE
- I
OUT1
, I
OUT
= 850 mA,
22
33
38
mA
V
SENSE
= 0 V, V
CC
= 5 V
Output Saturation Voltage
V
CE(SAT)
V
SENSE
= 0.4 V, V
CC
= 3.0 V:
BRAKE = H
Source Driver, I
OUT
= -0.85 A
--
1.0
1.1
V
(Forward/Reverse Mode)
Source Driver, I
OUT
= -1.3 A
--
1.7
1.9
V
Sink Driver, I
OUT
= 0.85 A
--
0.4
0.5
V
Sink Driver, I
OUT
= 1.3 A
--
1.1
1.3
V
Output Saturation Voltage
V
CE(SAT)
V
SENSE
= 0.4 V, V
CC
= 3.0 V:
BRAKE = L
Sink Driver, I
OUT
= 0.85 A
--
1.0
1.2
V
(Brake Mode)
Sink Driver, I
OUT
= 1.3 A
--
1.3
1.5
V
Clamp Diode Forward Voltage
V
F
I
F
= 0.85 A
--
1.2
1.4
V
(Sink or Source)
I
F
= 1.3 A
--
1.4
1.6
V
Continued next page...
Power Outputs
3953
FULL-BRIDGE
PWM MOTOR DRIVER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
4
PWM RC Fixed Off-time
t
OFF RC
C
T
= 680 pF, R
T
= 30 k
, V
CC
= 3.3 V
18.3
20.4
22.5
s
PWM Turn-Off Time
t
PWM(OFF)
Comparator Trip to Source Off,
--
1.0
1.5
s
I
OUT
= 25 mA
Comparator Trip to Source Off,
--
1.8
2.6
s
I
OUT
= 1.3 A
PWM Turn-On Time
t
PWM(ON)
I
RC
Charge On to Source On,
--
0.4
0.7
s
I
OUT
= 25 mA
I
RC
Charge On to Source On,
--
0.55
0.85
s
I
OUT
= 1.3 A
PWM Minimum On Time
t
ON(min)
V
CC
= 3.3 V, R
T
12 k
, C
T
= 680 pF
0.8
1.4
1.9
s
V
CC
= 5.0 V, R
T
12 k
, C
T
= 470 pF
0.8
1.6
2.0
s
Propagation Delay Times
t
pd
I
OUT
=
1.3 A, 50% to 90%:
ENABLE On to Source On
--
1.0
--
s
ENABLE Off to Source Off
--
1.0
--
s
ENABLE On to Sink On
--
1.0
--
s
ENABLE Off to Sink Off (MODE = L)
--
0.8
--
s
PHASE Change to Sink On
--
2.4
--
s
PHASE Change to Sink Off
--
0.8
--
s
PHASE Change to Source On
--
2.0
--
s
PHASE Change to Source Off
--
1.7
--
s
Crossover Dead Time
t
CODT
1 k
Load to 25 V, V
BB
= 50 V
0.3
1.5
3.0
s
Maximum PWM Frequency
f
PWM(max)
I
OUT
= 1.3 A
70
--
--
kHz
ELECTRICAL CHARACTERISTICS at T
J
= 25C, 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
Continued next page...
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