Description

Designed for pulse width modulated (PWM) current control of

bipolar microstepped stepper motors, the A3992 is capable of

continuous output currents to ±1.5 A and operating voltages to

50 V. Internal fixed off-time PWM current control timing circuitry

can be programmed via the serial interface to operate in slow, fast,

or mixed decay modes.

The desired load current level is set via the serial port with two

six bit linear DACs in conjunction with a reference voltage. The

six bits of control allow maximum flexibility in torque control for

a variety of step methods, from microstepping to full step drive.

Load current is set in 1.56% increments of the maximum value.

Synchronous rectification circuitry allows the load current to flow

decay. This feature eliminates the need for external clamp diodes

in most applications, saving cost and external component count,

while minimizing power dissipation.

Internal circuit protection includes short-to-ground, shorted load,

thermalshutdownwithhysteresis,andcrossovercurrentprotection.

Special power up sequencing is not required.

The A3992 is supplied in a thin profile (1.2 mm maximum height)

24 pin TSSOP (suffix LP) with exposed thermal pad and a 24 pin

plastic DIP with dual copper batwing tabs (suffix B). The exposed

thermal pad on the LPis at ground potential and needs no electrical

isolation. Both packages are lead (Pb) free with 100% matte tin

leadframe plating.

3992DS

Features and Benefits

▪ ±1.5 A, 50 V continuous output rating

▪ Short-to-ground protection

▪ Shorted load protection

▪ Optimized microstepping via six bit linear DACs

▪ Programmable mixed, fast, and slow current decay modes

▪ 4 MHz internal oscillator for digital timing

▪ Serial interface controls chip functions

▪ Synchronous rectification for low power dissipation

▪ Internal UVLO and thermal shutdown circuitry

▪ Crossover-current protection

▪ Inputs compatible with 5 or 3.3 V control signals

▪ Sleep and Idle modes

DMOS Dual Full-Bridge Microstepping PWM Motor Driver

Packages

Typical Application

LP package approximate scale

A3992

24 pin batwing DIP (suffix B) and 24 pin TSSOP with

exposed thermal pad (suffix LP)

Microcontroller or

Controller Logic

CLOCK

ROSC

VDD

VREG

CP1

CP2

VCP

VBB1

VBB2

OUT1A

OUT1B

SENSE1

SENSE2

OUT2A

OUT2B

DATA

STROBE

REF

SLEEP

A3992

0.22 μF

0.22 μF

100 μF

0.1 μF

0.1 μF

0.22 μF

10 μF

5 kΩ