Stepper Motor Driver features built-in translator.

Press Release Summary:

Offering DMOS outputs rated at 35 V and ±1.5 A, A3982 bipolar stepper motor driver is controlled with 2-wire STEP and DIRECTION interface for operation in full- or half-step modes. Device comes in 24-pin SOIC package with 15.4 x 7.5 mm footprint and internal synchronous rectification control circuitry. Along with fixed off-time output current regulator, which automatically selects slow- or mixed-decay modes, unit offers internal circuit protection.

Original Press Release:

Allegro MicroSystems, Inc. Announces Stepper Motor Driver with Built-In Translator

Worcester, MA - April 7, 2005 - Allegro MicroSystems, Inc. announces the release of the A3982, a new bipolar stepper motor driver with DMOS outputs rated at 35 V and ±1.5 A (2 A peak). Low ON resistance DMOS outputs, along with synchronous rectification, result in low-power dissipation, allowing higher motor currents and reduced temperature rise. Controlled with a simple two-wire STEP and DIRECTION interface for easy operation in full- or half-step modes, this device comes in a 24-pin SOIC package (15.4 x 7.5 mm) that is 20 to 50 percent smaller than competitive ICs in the same current range.

The translator is key to the easy implementation of the A3982. By simply inputting one pulse on the step input, the motor will take one step. There are no phase sequence tables, high-frequency control lines or complex interfaces to program. The simple, two-input STEP and DIRECTION interface of the A3982 makes it ideal for applications with multiple motors that would normally push the I/O capacity of most microprocessor controllers.

Internal synchronous rectification control circuitry is included in the A3982 to improve power dissipation during PWM operation. The power dissipation savings (typically greater than 20 percent) will result in lower temperature rise and eliminate the need for external Schottky diodes. Competitive devices with bipolar outputs cannot implement synchronous rectification.

The A3982 includes a fixed off-time output current regulator, which automatically selects slow- or mixed-decay modes. This patented current decay scheme results in reduced audible noise, increased step accuracy and reduced power dissipation. Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout and crossover current protection. Special power-up sequencing is not required

Targeted at the office automation and industrial markets, the A3982 is manufactured using the Allegro® ABCD (Allegro Bipolar CMOS DMOS) process and is offered in an industry-standard 24-lead SOIC (suffix 'LB'). Pricing is $1.80 per part for quantities of 10,000.

Allegro MicroSystems, Inc. is a supplier of advanced mixed-signal power semiconductors and Hall-effect sensors targeted toward the automotive, communications, computer/office automation, consumer and industrial markets. It maintains a leadership position in the integrated magnetic sensor and integrated motor driver product segments. With over 2,000 employees, Allegro is headquartered in Worcester, MA. Further information about Allegro, as well as free samples on our products, can be found at

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