A4973
Full-Bridge PWM Motor Driver
Features and Benefits
Description
▪ ±1.5 A continuous output current
▪ 50 V output voltage rating
▪ 3 V to 5.5 V logic supply voltage
▪ Internal PWM current control
▪ Fast and slow current-decay modes
▪ Sleep (low current consumption) mode
▪ Internal transient-suppression diodes
▪ Internal thermal shutdown circuitry
▪ Crossover current and UVLO protection
Designed for bidirectional pulse width modulated (PWM)
current control of inductive loads, the A4973 is capable of
continuous output currents to ±1.5 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.
Packages:
Package B, 16-pin DIP
with exposed tabs
Package LB, 16-pin SOIC
with internally fused pins
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.
Not to scale
Continued on the next page…
6 V CC
LOAD
SUPPLY
OUT A
9
OUT B
LOGIC
SUPPLY
LOAD
SUPPLY
Functional Block Diagram
15
10
16
SLEEP &
STANDBY MODES
MODE
14
PHASE
7
V BB
ENABLE
8
BRAKE
1
INPUT LOGIC
UVLO
& TSD
PWM LATCH
–
Q
4
SENSE
2
S
BLANKING
GROUND
11
+
R
V CC
RS
RC
3
5
12
+ –
2
REF
RT
4973DS, Rev. 1
CT
V TH
13
GROUND
A4973
Full-Bridge PWM Motor Driver
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 A4973 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-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).
Selection Guide
Part Number
A4973SB-T
A4973SLBTR-T
Package
16-pin DIP with exposed thermal tabs
16-pin SOICW with internally-fused pins
Packing
25 pieces per tube
1000 pieces per reel
Absolute Maximum Ratings
Characteristic
Symbol
Rating
Units
50
V
VCC
6
V
VIN
–0.3 to 6
V
0.5
V
±1.5
A
6
A
Load Supply Voltage
VBB
Logic Supply Voltage
Logic/Reference Input Voltage Range
Sense Voltage
Notes
VSENSE
Output Current, Continuous
IOUT
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.
Transient Output Current
IOUT
tW < 2 μs
Package Power Dissipation
PD
Operating Ambient Temperature
TA
Maximum Junction Temperature
TJ(max)
Storage Temperature
Range S
See graph
W
–20 to 85
ºC
150
ºC
–55 to 150
ºC
Value
Units
43
ºC/W
67
ºC/W
6
ºC/W
Fault conditions that produce excessive junction temperature
will activate the device’s thermal shutdown circuitry. These
conditions can be tolerated but should be avoided.
Tstg
Thermal Characteristics
Characteristic
Symbol
Test Conditions*
B Package, single-layer PCB, 1 in.2 2-oz. exposed copper
Package Thermal Resistance, Junction
to Ambient
RθJA
Package Thermal Resistance, Junction
to Tab
RθJT
LB Package, 2-layer PCB, 0.3
side
in.2
2-oz. exposed copper each
Note the A4973SB (DIP) and
the A4973SLB (SOIC) are
electrically identical and share
a common terminal number
assignment.
16
LOAD
SUPPLY
2
15
OUTB
RC
3
14
MODE
GROUND
4
13
GROUND
GROUND
5
LOGIC
SUPPLY
6
PHASE
7
ENABLE
8
BRAKE
1
REF
VBB
LOGIC
VCC
VBB
12
GROUND
11
SENSE
10
OUTA
9
LOAD
SUPPLY
Dwg. PP-056
ALLOWABLE PACKAGE POWER DISSIPATION (W)
*Additional thermal information available on Allegro website.
4
R θJT = 6.0°C/W
3
SUFFIX 'B', R θJA = 43°C/W
2
1
SUFFIX 'LB', R θJA = 67°C/W
0
25
50
75
100
TEMPERATURE IN °C
125
150
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A4973
Full-Bridge PWM Motor Driver
ELECTRICAL CHARACTERISTICS at TJ = 25°C, VCC = 3.0 V to 5.5 V (unless otherwise noted.)
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Unit
Operating
5
–
50
V
VOUT = VBB
–
<1.0
50
μA
Power Outputs
Load Supply Voltage Range
VBB
Output Leakage Current
ICEX
VOUT = 0 V
–
<–1.0
–50
μA
RDS(on)
Total sink and source, IOUT = 1.5 A, VBB > 8 V, TJ = 25°C
–
1
1.4
Ω
PWM RC Fixed Off-time
tOFF RC
CT = 680 pF, RT= 30 kΩ, VCC = 3.3 V
18.3
20.4
22.5
μs
PWM Minimum On Time
tON(min)
VCC = 3.3 V, RT ≥ 12 kΩ, CT = 680 pF
0.8
1.4
1.9
μs
VCC = 5.0 V, RT ≥ 12 kΩ, CT = 470 pF
0.8
1.6
2.0
μs
–
500
–
ns
70
–
–
kHz
TJ
–
165
–
°C
∆TJ
–
15
–
°C
2.5
2.75
3.0
V
Output On Resistance
AC Timing
Crossover Dead Time
Maximum PWM Frequency
tCODT
fPWM(max)
IOUT = 1.5 A
Control Circuitry
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
UVLO Enable Threshold
UVLO Hysteresis
Logic Supply Current
Motor Supply Current (No Load)
Logic Supply Voltage Range
ICC(ON)
ICC(Sleep)
IBB(ON)
IBB(Sleep)
VCC
0.12
0.17
0.25
V
VENABLE = VIN(0) , VBRAKE = VIN(1)
–
2.7
3.5
mA
VENABLE = VMODE = VBRAKE = VIN(1)
–
250
450
μA
VENABLE = VIN(0)
–
500
700
μA
VENABLE = VMODE = VBRAKE = VIN(1)
Operating
VIN(1)
Logic Input Voltage
–
<1.0
3
μA
3.0
VCC ×
0.55
5.0
5.5
V
–
–
V
–
–
IIN(1)
VIN = VCC = 5 V
—
0
VCC ×
0.27
–10
IIN(0)
VIN = 0 V, VCC = 5 V
—
–106
–200
Reference Input Current
IREF
VREF = 0 V to 1 V
–
–
±5.0
μA
Comparator Input Offset Volt.
VIO
VREF = 0 V
–
±2.0
±5.0
mV
REF Pin
0
–
1
V
1.9
2
2.1
–
VIN(0)
Logic Input Current
Reference Input Voltage Range
Gain
VREF
VREF = 1 V
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
V
μA
μA
3
A4973
Full-Bridge PWM Motor Driver
FUNCTIONAL DESCRIPTION
Internal PWM Current Control During Forward
and Reverse Operation. The A4973 contains a fixed
off-time pulse width modulated (PWM) current-control circuit
that can be used to limit the load current to a desired value. The
peak value of the current limiting (ITRIP) is set by the selection
of an external current sensing resistor (RS) and reference input
voltage (VREF). The internal circuitry compares the voltage
across the external sense resistor to the voltage on the reference
input terminal (REF) resulting in a transconductance function
approximated by:
VREF
ITRIP ≈
2 × RS
In forward or reverse mode the current-control circuitry limits
the load current as follows: when the load current reaches ITRIP,
the comparator resets a latch that turns off the selected source
driver or selected sink and source driver pair depending on
whether the device is operating in slow or fast current-decay
mode, respectively.
In slow current-decay mode, the selected source driver is
disabled and both sinks are turned on. The load inductance
causes the current to recirculate through the sink drivers. In fast
current-decay mode, the selected sink and source driver pair are
disabled, then the opposite pair is turned on. The load inductance
causes the current to flow from ground to the load supply via the
motor winding and the opposite pair of transistors (see figure 1).
Figure 1 — Load-Current Paths
VBB
The user selects an external resistor (RT) and capacitor (CT) to
determine the time period (tOFF = RT x CT) during which the
drivers remain disabled (see RC Fixed Off-Time section, below).
At the end of the RC interval, the drivers are enabled allowing
the load current to increase again. The PWM cycle repeats,
maintaining the peak load current at the desired value (figure 2).
Figure 2
Fast and Slow Current-Decay Waveforms
ENABLE
MODE
I
TRIP
RC
LOAD
CURRENT
RC
Dwg. WP-015-1
Brake Operation. During braking, care should be taken
to ensure that the motor’s current does not exceed the ratings
of the device. The braking current can be measured by using
an oscilloscope with a current probe connected to one of the
motor’s leads, or if the back-EMF voltage of the motor is known,
approximated by:
IPEAK BRAKE ML ≈
VBEMF
RLOAD
RC Fixed Off-Time. The internal PWM current-control
circuitry uses a one shot to control the time the driver(s)
remain(s) off. The one-shot time, tOFF (fixed off-time), is
determined by the selection of an external resistor (RT) and
capacitor (CT) connected in parallel from the RC timing terminal
to ground. The fixed off-time, over a range of values of CT = 470
pF to 1500 pF and RT = 12 kΩ to 100 kΩ, is approximated by:
tOFF ≈ RT x CT
RS
Drive Current (Normal)
Recirculation (Fast Decay)
Recirculation (Slow Decay)
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115 Northeast Cutoff
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4
A4973
Full-Bridge PWM Motor Driver
TRUTH TABLE
BRAKE
ENABLE
PHASE
MODE
OUTA
OUTB
DESCRIPTION
H
H
X
H
Off
Off
H
H
X
L
Off
Off
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
X
L
L
Brake
Sleep Mode
Standby
X = Don’t care.
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115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
A4973
The operation of the circuit is as follows: when the PWM latch is
reset by the current comparator, the voltage on the RC terminal
will begin to decay from approximately 0.60VCC. When the
voltage on the RC terminal reaches approximately 0.22VCC, the
PWM latch is set, thereby enabling the driver(s).
RC Blanking. In addition to determining the fixed off-time of
the PWM control circuit, the CT component sets the comparator
blanking time. This function blanks the output of the comparator
when the outputs are switched by the internal current-control
circuitry (or by the PHASE, BRAKE, or ENABLE inputs).
The comparator output is blanked to prevent false over-current
detections due to reverse recovery currents of the clamp diodes,
and/or switching transients related to distributed capacitance in
the load.
During internal PWM operation, at the end of the tOFF time, the
comparator’s output is blanked and CT begins to be charged
from approximately 0.22VCC by an internal current source of
approximately 1 mA. The comparator output remains blanked
until the voltage on CT reaches approximately 0.60VCC.
Full-Bridge PWM Motor Driver
LOAD CURRENT REGULATION
WITH INTERNAL PWM
CURRENT-CONTROL CIRCUITRY
When the device is operating in slow current-decay mode,
there is a limit to the lowest level that the PWM currentcontrol circuitry can regulate load current. The limitation is the
minimum duty cycle, which is a function of the user-selected
value of tOFF and the minimum on-time pulse tON(min) max that
occurs each time the PWM latch is reset. If the motor is not
rotating (as in the case of a stepper motor in hold/detent mode, a
brush dc motor when stalled, or at startup), the worst case value
of current regulation can be approximated by:
{ [ VBB – (2 × I × RDS) ] × tON(min)max } – [1.05 (I × RDS + VF) × tOFF ]
IAVE ≈
1.05 × (tON(min)max + tOFF) × RLOAD
When a transition of the PHASE input occurs, CT is discharged
to near ground during the crossover delay time (the crossover
delay time is present to prevent simultaneous conduction of
the source and sink drivers). After the crossover delay, CT is
charged by an internal current source of approximately 1 mA.
The comparator output remains blanked until the voltage on CT
reaches approximately 0.60VCC.
where tOFF = RT x CT, RLOAD is the series resistance of the load,
VBB is the motor supply voltage and t ON(min)max is specified in
the Electrical Characteristics table. When the motor is rotating,
the back EMF generated will influence the above relationship.
For brush dc motor applications, the current regulation is
improved. For stepper motor applications, when the motor is
rotating, the effect is more complex. A discussion of this subject
is included in the section on stepper motors below.
The following procedure can be used to evaluate the worst-case
slow current-decay internal PWM load current regulation in the
system:
When the device is disabled, via the ENABLE input, CT is
discharged to near ground. When the device is re-enabled, CT is
charged by an internal current source of approximately 1 mA.
The comparator output remains blanked until the voltage on CT
reaches approximately 0.60VCC.
1. Set VREF to 0 volts. With the load connected and the PWM
current control operating in slow current-decay mode, use an
oscilloscope to measure the time the output is low (sink on) for
the output that is chopping. This is the typical minimum on time
(tON(min) typ) for the device.
For 3.3 V operation, the minimum recommended value
for CT is 680 pF ± 5 %. For 5.0 V operation, the minimum
recommended value for CT is 470 pF ± 5%. These values
ensure that the blanking time is sufficient to avoid false trips
of the comparator under normal operating conditions. For
optimal regulation of the load current, the above values for CT
are recommended and the value of RT can be sized to determine
tOFF. For more information regarding load current regulation, see
below.
2. The CT then should be increased until the measured value
of tON(min) is equal to tON(min) max as specified in the electrical
characteristics table.
3. When the new value of CT has been set, the value of RT should
be decreased so the value for tOFF = RT x CT (with the artificially
increased value of CT) is equal to the nominal design value.
4. The worst-case load-current regulation then can be measured
in the system under operating conditions.
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115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
A4973
PWM of the PHASE and ENABLE Inputs. The
PHASE and ENABLE inputs can be pulse-width modulated
to regulate load current. If the internal PWM current control is
used, the comparator blanking function is active during phase
and enable transitions. This eliminates false tripping of the
over-current comparator caused by switching transients (see RC
Blanking section, above).
Enable PWM. With the MODE input low, toggling the
ENABLE input turns on and off the selected source and sink
drivers. The corresponding pair of intrinsic flyback and groundclamp diodes conduct after the drivers are disabled, resulting
in fast current decay. When the device is enabled the internal
current-control circuitry will be active and can be used to limit
the load current in a slow current-decay mode.
For applications that PWM the ENABLE input and desire the
internal current-limiting circuit to function in the fast decay
mode, the ENABLE input signal should be inverted and
connected to the MODE input. This prevents the device from
being switched into sleep mode when the ENABLE input is low.
Phase PWM. Toggling the PHASE terminal selects which
sink/source pair is enabled, producing a load current that varies
with the duty cycle and remains continuous at all times. This
can have added benefits in bidirectional brush dc servo motor
applications as the transfer function between the duty cycle on
the PHASE input and the average voltage applied to the motor is
more linear than in the case of ENABLE PWM control (which
produces a discontinuous current at low current levels). For more
information see DC Motor Applications section, below.
Synchronous Fixed-Frequency PWM. The internal
PWM current-control circuitry of multiple A4973 devices can
be synchronized by using the simple circuit shown in figure 3.
A 555 IC can be used to generate the reset pulse/blanking signal
(t1) for the device and the period of the PWM cycle (t2). The
value of t1 should be a minimum of 1.5 ms. When used in this
configuration, the RT and CT components should be omitted. The
PHASE and ENABLE inputs should not be PWMed with this
circuit configuration due to the absence of a blanking function
synchronous with their transitions.
Full-Bridge PWM Motor Driver
only to protect the device from failures due to excessive junction
temperatures and should not imply that output short circuits
are permitted. The hysteresis of the thermal shutdown circuit is
approximately 15°C.
APPLICATION NOTES
Current Sensing. The actual peak load current (IPEAK) will
be above the calculated value of ITRIP due to delays in the turn
off of the drivers. The amount of overshoot can be approximated
by:
(VBB – [(ITRIP x RLOAD) + VBEMF]) x tPWM(OFF)
IOS ≈
LLOAD
where VBB is the motor supply voltage, VBEMF is the back-EMF
voltage of the load, RLOAD and LLOAD are the resistance and
inductance of the load respectively, and tPWM(OFF) is specified in
the electrical characteristics table.
The reference terminal has a maximum input bias current
of ±5 μA. This current should be taken into account when
determining the impedance of the external circuit that sets the
reference voltage value.
To minimize current-sensing inaccuracies caused by ground
trace I x R drops, the current-sensing resistor should have a
separate return to the ground terminal of the device. For lowvalue sense resistors, the I x R drops in the printed wiring board
can be significant and should be taken into account. The use of
sockets should be avoided as their contact resistance can cause
variations in the effective value of RS.
Generally, larger values of RS reduce the aforementioned effects
but can result in excessive heating and power loss in the sense
resistor. The selected value of RS should not cause the absolute
maximum voltage rating of 500 mV, for the SENSE terminal, to
be exceeded.
Figure 3
Synchronous Fixed-Frequency Control Circuit
V CC
t
2
20 kΩ
the ENABLE and MODE terminals puts the device into a sleep
mode to minimize current consumption when not in use.
An internally generated dead time prevents crossover currents
that can occur when switching phase or braking.
Thermal protection circuitry turns off all drivers should the
junction temperature reach 165°C (typical). This is intended
100 kΩ
Miscellaneous Information. A logic high applied to both
RC 1
1N4001
2N2222
t
RC N
1
Dwg. EP-060
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115 Northeast Cutoff
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7
A4973
Full-Bridge PWM Motor Driver
The current-sensing comparator functions down to ground
allowing the device to be used in microstepping, sinusoidal, and
other varying current-profile applications.
switching losses in the device and iron losses in the motor. This
also improves the maximum rate at which the load current can
increase (as compared to fast decay) due to the slow rate of decay
during tOFF. When the load current is decreasing, fast-decay mode
Thermal Considerations. For reliable operation it is
is used to regulate the load current to the desired level. This
recommended that the maximum junction temperature be kept
below 110°C to 125°C. The junction temperature can be measured prevents tailing of the current profile caused by the back-EMF
best by attaching a thermocouple to the power tab/batwing of the voltage of the stepper motor.
device and measuring the tab temperature, TTAB. The junction
In stepper-motor applications applying a constant current to
temperature can then be approximated by using the formula:
the load, slow-decay mode PWM is typically used to limit the
2
TJ ≈ TTAB + I LOAD × RDS(on) x RθJT
switching losses in the device and iron losses in the motor.
DC Motor Applications. In closed-loop systems, the
The power dissipation of the batwing packages can be improved
by 20% to 30% by adding a section of printed circuit board
copper (typically 6 to 18 square centimeters) connected to the
batwing terminals of the device.
speed of a dc motor can be controlled by PWM of the PHASE
or ENABLE inputs, or by varying the reference input voltage
(REF). In digital systems (microprocessor controlled), PWM of
the PHASE or ENABLE input is used typically thus avoiding
the need to generate a variable analog voltage reference. In this
case, a dc voltage on the REF input is used typically to limit the
maximum load current.
PCB Layout. The load supply terminal, VBB, should
be decoupled with an electrolytic capacitor (>47 μF is
recommended) placed as close to the device as is physically
practical. To minimize the effect of system ground I x R drops on
the logic and reference input signals, the system ground should
have a low-resistance return to the motor supply voltage. See also
the Current Sensing and Thermal Considerations sections, above.
In dc servo applications, which require accurate positioning
at low or zero speed, PWM of the PHASE input is selected
typically. This simplifies the servo control loop because the
transfer function between the duty cycle on the PHASE input and
the average voltage applied to the motor is more linear than in the
case of ENABLE PWM control (which produces a discontinuous
current at low current levels).
Fixed Off-Time Selection. With increasing values of tOFF,
switching losses will decrease, low-level load-current regulation
will improve, EMI will be reduced, the PWM frequency will
decrease, and ripple current will increase. The value of tOFF can
be chosen for optimization of these parameters. For applications
where audible noise is a concern, typical values of tOFF are chosen
to be in the range of 15 to 35 μs.
With bidirectional dc servo motors, the PHASE terminal can be
used for mechanical direction control. Similar to when braking
the motor dynamically, abrupt changes in the direction of a
rotating motor produces a current generated by the back-EMF.
The current generated will depend on the mode of operation. If
the internal current control circuitry is not being used, then the
maximum load current generated can be approximated by ILOAD =
(VBEMF + VBB)/RLOAD where VBEMF is proportional to the motor’s
speed. If the internal slow current-decay control circuitry is used,
then the maximum load current generated can be approximated
by ILOAD = VBEMF/RLOAD. For both cases care must be taken to
The value for RθJT is given in the package thermal resistance table
for the appropriate package.
Stepper Motor Applications. The MODE terminal can be
used to optimize the performance of the device in microstepping/
sinusoidal stepper-motor drive applications. When the load
current is increasing, slow decay mode is used to limit the
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
A4973
Full-Bridge PWM Motor Driver
ensure that the maximum ratings of the device are not exceeded.
If the internal fast current-decay control circuitry is used, then the
load current will regulate to a value given by:
the voltage rating of any devices connected to the motor supply.
See also the Brake Operation section, above.
Soldering Considerations. The lead (Pb) free (100%
matte tin) plating on lead terminations is 100% backwardcompatible for use with traditional tin-lead solders of any
composition, at any temperature of soldering that has been
traditionally used for that tin-lead solder alloy. Further, 100%
matte tin finishes solder well with tin-lead solders even at
temperatures below 232°C. This is because the matte tin dissolves
easily in the tin-lead. Additional information on soldering is
available on the Allegro Web site, www.allegromicro.com.
ILOAD = VREF / (RS × 2)
CAUTION: In fast current-decay mode, when the direction of
the motor is changed abruptly, the kinetic energy stored in the
motor and load inertia will be converted into current that charges
the VBB supply bulk capacitance (power supply output and
decoupling capacitance). Care must be taken to ensure that the
capacitance is sufficient to absorb the energy without exceeding
Figure 4 — Typical Application
V
+5 V
2
15
3
14
VBB
4
LOGIC
PHASE
7
ENABLE
8
VCC
47 MF
MODE
13
12
5
6
16
0.5 7
30 k 7
REF
470 pF
1
+
BRAKE
BB
11
10
VBB
9
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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9
A4973
Full-Bridge PWM Motor Driver
B package 16-pin DIP
19.05±0.25
16
+0.10
0.38 –0.05
+0.76
6.35 –0.25
+0.38
10.92 –0.25
7.62
A
1
2
5.33 MAX
+0.51
3.30 –0.38
1.27 MIN
+0.25
1.52 –0.38
2.54
For Reference Only
(reference JEDEC MS-001 BB)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
A Terminal #1 mark area
0.46 ±0.12
LB package 16-pin SOICW
10.30±0.20
4° ±4
16
1.27
0.65
+0.07
0.27 –0.06
10.30±0.33
7.50±0.10
A
9.50
+0.44
0.84 –0.43
2.25
1
2
0.25
16X
SEATING
PLANE
0.10 C
0.41 ±0.10
1.27
2.65 MAX
0.20 ±0.10
C
SEATING PLANE
GAUGE PLANE
B
PCB Layout Reference View
For Reference Only
Pins 4 and 5, and 12 and 13 internally fused
Dimensions in millimeters
(reference JEDEC MS-013 AA)
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
A Terminal #1 mark area
B Reference pad layout (reference IPC SOIC127P1030X265-16M)
All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
10
A4973
Full-Bridge PWM Motor Driver
Revision History
Revision
Revision Date
Rev. 1
October TBD, 2012
Description of Revision
Update Absolute Maximum Ratings
Copyright ©2009-2013, Allegro MicroSystems, LLC
Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to
permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that
the information being relied upon is current.
Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the
failure of that life support device or system, or to affect the safety or effectiveness of that device or system.
The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use;
nor for any infringement of patents or other rights of third parties which may result from its use.
For the latest version of this document, visit our website:
www.allegromicro.com
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
11