A3969
Dual Full-Bridge PWM Motor Driver
Features and Benefits
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±650 mA Continuous Output Current
30 V Output Voltage Rating
Internal Fixed-Frequency PWM Current Control
Satlington Sink Drivers
User-Selectable Blanking Window
Internal Ground-Clamp and Flyback Diodes
Internal Thermal-Shutdown Circuitry
Crossover-Current Protection and UVLO Protection
Description
The A3969 is designed to drive both windings of a two-phase
bipolar stepper motor. The device includes two H-bridges
capable of continuous output currents of ±650 mA and operating
voltages to 30 V. Motor winding current can be controlled by
the internal fixed-frequency, pulse-width modulated (PWM),
current-control circuitry. The peak load current limit is set by
the user’s selection of a reference voltage and current-sensing
resistors.
The fixed-frequency pulse duration is set by a user-selected
external RC timing network. 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.
To reduce on-chip power dissipation, the H-bridge power
outputs have been optimized for low saturation voltages. The
sink drivers feature the Allegro
®
patented Satlington
®
output
structure. The Satlington outputs combine the low voltage drop
of a saturated transistor and the high peak current capability
of a Darlington.
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Package: 28 pin QFN (suffix ET)
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Approximate scale
Typical Application
+3.3 V
+24 V
+3.3 V
20 kΩ
10 kΩ
56 kΩ
680 pF
47 μF
28
27
26
25
24
23
22
21
20
19
0.5 Ω
18
17
16
EN1
PH1
15
0.5 Ω
1
2
3
4
5
LOGIC
LOGIC
EN2
PH2
6
7
V
BB
10
12
13
DS3969
14
11
8
9
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
