A3989 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – Bipolar Stepper and High Current DC Motor Driver

A3989
Bipolar Stepper and High Current DC Motor Driver
Features and Benefits
▪ 36 V output rating
▪ 2.4 A dc motor driver
▪ 1.2 A bipolar stepper driver
▪ Synchronous rectification
▪ Internal undervoltage lockout (UVLO)
▪ Thermal shutdown circuitry
▪ Crossover-current protection
▪ Very thin profile QFN package
Package: 36 pin QFN with exposed thermal pad
0.90 mm nominal height (suffix EV)
Approximate scale 1:1
Description
The A3989 is designed operate at voltages up to 36 V while driving
one bipolar stepper motor, at currents up to 1.2A, and one dc motor,
at currents up to 2.4 A. The A3989 includes a fixed off-time pulse
width modulation (PWM) regulator for current control. The stepper
motor driver features dual 2-bit nonlinear DACs (digital-to-analog
converters) that enable control in full, half, and quarter steps. The
dc motor is controlled using standard PHASE and ENABLE signals.
Fast or slow current decay is selected via the MODE pin. The PWM
current regulator uses the Allegro^® patented mixed decay mode for
reduced audible motor noise, increased step accuracy, and reduced
power dissipation.
Internal synchronous rectification control circuitry is provided to
improve power dissipation during PWM operation.
Protection features include thermal shutdown with hysteresis,
undervoltage lockout (UVLO) and crossover current protection.
Special power up sequencing is not required.
The A3989 is supplied in a leadless 6 mm × 6 mm × 0.9 mm,
36 pin QFN package with exposed power tab for enhanced thermal
performance. The package is lead (Pb) free, with 100% matte tin
leadframe plating.
Microcontroller or
Controller Logic
A3989DS
0.1 µF
50 V
CP1
VDD
0.1 µF
50 V
CP2 VCP
VBB VBB
100 µF
50 V
OUT1A
PHASE1
I01
A3989
I11
PHASE2
I02
I12
PHASE3
ENABLE
MODE
VREF1
VREF2
VREF3
GND GND
OUT1B
SENSE1
OUT2A
OUT2B
SENSE2
OUT3A
OUT3A
OUT3B
OUT3B
SENSE3
SENSE3
Figure 1. Typical application circuit
0.22 µF
50 V