A4973
Full-Bridge PWM Motor Driver
FEATURES AND BENEFITS DESCRIPTION
1.5 A continuous output current Designed for bidirectional pulse-width-modulated (PWM)
50 V output voltage rating current control of inductive loads, the A4973 is capable of
3 to 5.5 V logic supply voltage continuous output currents to 1.5 A and operating voltages
Internal PWM current control to 50 V. Internal fixed off-time PWM current control circuitry
Fast and slow current decay modes can be used to regulate the maximum load current to a desired
Sleep (low current consumption) mode value. The peak load current limit is set by the users selection
Internal transient-suppression diodes of an input reference voltage and external sensing resistor. The
Internal thermal shutdown circuitry fixed off-time pulse duration is set by a user-selected external
Crossover current and UVLO protection RC timing network. Internal circuit protection includes thermal
shutdown with hysteresis, transient suppression diodes, and
crossover current protection. Special power-up sequencing is
PACKAGES:
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
Package B, 16-pin DIP Package LB, 16-pin SOIC
held high, all output drivers are disabled. A sleep mode is
with exposed tabs with internally fused pins
provided to reduce power consumption.
Not to scale
Continued on the next page
Functional Block Diagram
LOGIC
6 V 9 10 15
CC 16
SUPPLY
SLEEP &
STANDBY MODES
14
MODE
V BB
PHASE 7
UVLO
& TSD
8
ENABLE
1
BRAKE
PWM LATCH
11
R
SENSE
2
Q
S R
BLANKING S
GROUND
V
4 CC
12
RC
+
5 3 2 13
REF GROUND
V
TH
C
T
R
T
4973DS, Rev. 5 January 29, 2019
MCO-0000192
INPUT LOGIC
LOAD
SUPPLY
OUT
A
OUT
B
LOAD
SUPPLY
+A4973 Full-Bridge PWM Motor Driver
DESCRIPTION (CONTINUED)
When a logic low is applied to the BRAKE input, the braking 16-pin dual in-line plastic package with copper heat-sink tabs,
function is enabled. This overrides ENABLE and PHASE to turn
and a 16-pin plastic SOIC with copper heat-sink tabs. For both
off both source drivers and turn on both sink drivers. The brake
package styles, the power tab is at ground potential and needs no
function can be used to dynamically brake brush DC motors.
electrical isolation. Each package type is available in a lead (Pb)
The A4973 is supplied in a choice of two power packages: a free version (100% matte-tin-plated leadframe).
SELECTION GUIDE
Part Number Package Packing
A4973SB-T * 16-pin DIP with exposed thermal tabs 25 pieces per tube
A4973SLBTR-T 16-pin SOICW with internally-fused pins 1000 pieces per reel
* A4973SB-T is no longer in production. The device should not be purchased for new design applications. Samples are no longer
available. Date of status change: July 2, 2018. For existing customer transition, and for new customers or new applications, use
A4973SLBTR-T.
ABSOLUTE MAXIMUM RATINGS
Characteristic Symbol Notes Rating Units
Load Supply Voltage V 50 V
BB
Logic Supply Voltage V 6 V
CC
Logic/Reference Input Voltage Range V 0.3 to 6 V
IN
Sense Voltage V 0.5 V
SENSE
Output current rating may be limited by duty cycle, ambient
temperature, and heat sinking. Under any set of conditions, do
Output Current, Continuous I 1.5 A
OUT
not exceed the specified current rating or a junction tempera -
ture of 150C.
Transient Output Current I t < 2 s 6 A
OUT W
Package Power Dissipation P See graph (p. 3) W
D
Operating Ambient Temperature T Range S 20 to 85 C
A
Fault conditions that produce excessive junction temperature
Maximum Junction Temperature T (max) will activate the devices thermal shutdown circuitry. These 150 C
J
conditions can be tolerated but should be avoided.
Storage Temperature T 55 to 150 C
stg
2
Allegro MicroSystems, LLC
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com