A3964 Datasheet, PDF (1/7 Pages) Allegro MicroSystems – Dual Full-Bridge PWM Motor Driver

A3964
Dual Full-Bridge PWM Motor Driver
Features and Benefits
▪ ±800 mA continuous output current rating
▪ 30 V output voltage rating
▪ Internal PWM current control, saturated sink drivers
▪ Internally generated, precision 2.5 V reference
▪ Internal transient-suppression diodes
▪ Internal thermal-shutdown circuitry
▪ Crossover-current protection, UVLO protection
Package: 20 pin SOIC (suffix LB)
Not to scale
Description
Designed for pulse width modulated (PWM) current control
of bipolar stepper motors, the A3964 is capable of continuous
output currents to ±800 mA and operating voltages to 30 V.
Internal fixed off-time PWM current-control circuitry can be
used to regulate the maximum load current to a desired value.
An internal precision voltage reference is provided to improve
motor peak-current control accuracy. The peak load current
limit is set by the user’s selection of an external resistor divider
and current-sensing resistors.
The fixed off-time pulse duration is set by user-selected
external RC timing networks. The capacitor in the RC timing
network also determines a user-selectable blanking window
that prevents false triggering of the PWM current control
circuitry during switching transitions. This eliminates the need
for two external RC filter networks on the current-sensing
comparator inputs.
For each bridge the PHASE input controls load current polarity
by selecting the appropriate source and sink driver pair. For
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Functional Block Diagram
17
VCC
PHASE ₁ 9
ENABLE1 10
SOURCE
DISABLE
ONE SHOT
–
+
3
1
4
VBB
1
2.5 V
REFERENCE
V REF(IN)
18 20
UVLO
& TSD
12 _{PHASE 2}
2
11 ENABLE2
SOURCE
DISABLE
–
+
ONE SHOT
8
RT
CT
29319.28g
2
14
7
5 6 15 16
19
RA
RB
RS
RS
13
CT
RT
Dwg. FP-033-1