Note the A3953SB (DIP) and the A3953SLB
(SOIC) are electrically identical and share a
common terminal number assignment.
4
5
LOGIC
PHASE
V
6
CC
7
89
LOGIC
V
BB
V
BB
16
15
14
13
12
11
10
LOAD
SUPPLY
OUT
B
MODE
GROUND
GROUND
SENSE
OUT
A
LOAD
SUPPLY
Dwg. PP-056
Data Sheet
29319.8c
3953
FULL-BRIDGE PWM MOTOR DRIVER
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 currentcontrol 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.
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, VBB. . . . . . . . . . 50 V
Output Current, I
(Continuous) . . . . . . . . . . . . . . ±1.3 A*
Logic Supply Voltage, V
Logic/Reference Input Voltage Range,
Junction Temperature, T
Storage Temperature Range,
. . . . . . . . . . . . . . . -55°C to +150°C
T
S
* 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.
† Fault conditions that produce excessive junction
temperature will activate the device’s thermal
shutdown circuitry. These conditions can be
tolerated but should be avoided.
OUT
SENSE
. . . . . . . . . 7.0 V
CC
. . . . . . . +150°C†
J
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-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-free version (100% matte tin plated leadframe).