Description
The A4970 motor driver drives both windings of a bipolar stepper
motor or bidirectionally controls two DC motors. Both bridges
are capable of sustaining 45 V and include internal pulse-width
modulation (PWM) control of the output current to 750 mA.
For PWM current control, the maximum output current is
determined by user selection of a reference voltage and sensing
resistor. Two logic-level inputs select output current limits of
0%, 33%, 67%, or 100% of the maximum level. A PHASE input
to each bridge determines load current direction.
Intrinsic diodes in the MOSFET output structure protect
against inductive transients. Internally generated delays prevent
crossover currents when switching current direction. Special
power-up sequencing is not required. Thermal protection
circuitry disables the outputs if the chip temperature exceeds
safe operating limits.
The device is supplied in a 24-pin surface-mount wide SOIC with
two pairs of batwing leads (LB). The webbed-pin construction
provides for maximum package power dissipation in the smallest
possible construction. The package is lead (Pb) free, with 100%
matte tin leadframe plating.
A4970CDS, Rev. 1
Features and Benefits
▪ 750 mA continuous output current
▪ 45 V output sustaining voltage
▪ Internal clamp diodes
▪ Internal PWM current control
▪ Low output saturation voltage
▪ Internal thermal shutdown circuitry
▪ Pin compatible with UDx2916
▪ DMOS outputs
Dual Full-Bridge PWM Motor Driver
Not to scale
A4970
PWM Current-Control Circuitry
VREF
VBB
M
SENSE
ONE
Divide by
1, 1.5, or 3
SHOT
SOURCE
DISABLE
RC
–
+
I
0
I
1
w10
E
OUT
A
OUTB
Channel 1
pin numbers
shown.
R
C
R
S
R
T
C
C
C
T
24
16
15
9
13
12
10
14
17
Package: 24-pin batwing wide SOIC
(package LB)
