A3986
Dual Full-Bridge MOSFET Driver
with Microstepping Translator
Features and Benefits
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2-wire step and direction interface
Dual full-bridge gate drive for N-channel MOSFETs
Operation over 12 to 50 V supply voltage range
Synchronous rectification
Cross-conduction protection
Adjustable mixed decay
Integrated sinusoidal DAC current reference
Fixed off-time PWM current control
Description
The A3986 is a dual full-bridge gate driver with integrated
microstepping translator suitable for driving a wide range of
higher power industrial bipolar 2-phase stepper motors (typically
30 to 500 W). Motor power is provided by external N-channel
power MOSFETs at supply voltages from 12 to 50 V.
This device contains two sinusoidal DACs that generate the
reference voltage for two separate fixed-off-time PWM current
controllers. These provide current regulation for external power
MOSFET full-bridges.
Motor stepping is controlled by a two-wire step and direction
interface, providing complete microstepping control at full-,
half-, quarter-, and sixteenth-step resolutions. The fixed-off
time regulator has the ability to operate in slow-, mixed-, or
fast-decay modes, which results in reduced audible motor noise,
increased step accuracy, and reduced power dissipation.
The translator is the key to the easy implementation of this
IC. Simply inputting one pulse on the STEP input drives the
motor one step (full, half, quarter, or sixteenth depending on
the microstep select input). There are no phase-sequence tables,
high frequency control lines, or complex interfaces to program.
This reduces the need for a complex microcontroller.
Package: 38 pin TSSOP (suffix LD)
Approximate size
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Typical Application Diagram
3986-DS, Rev. 1
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
