3986-DS, Rev. 1

Features and Benefits

▪ 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

Dual Full-Bridge MOSFET Driver

with Microstepping Translator

Continued on the next page…

Package: 38 pin TSSOP (suffix LD)

Typical Application Diagram

Approximate size

A3986

Description

The A3986 is a dual full-bridge gate driver with integrated

microstepping translator suitable for driving a wide range of

higherpowerindustrialbipolar2-phasesteppermotors(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.