Date: 01/07/2010

Dual full-bridge motor driver ICs from Allegro

Allegro has unveiled two new motor driver ICs, the A4986/A4987 devices, to complement their existing motor driver family. These are dual DMOS full-bridge stepper motor drivers with parallel input communication and overcurrent protection.

Some of the key features of A4986/A4987 are:
1. Each full-bridge output is rated up to 35 V and ±2 A.
2. They consists of a fixed off-time pulse width modulation (PWM) current regulator and 2-bit nonlinear DAC (digital-to-analog converter) that allows stepper motors to be controlled in full, half, and quarter step modes.
3. The PWM current regulator uses the Allegro's mixed decay mode for reduced audible motor noise, increased step accuracy, and reduced power dissipation.
4. It employs an internal synchronous rectification control circuitry to improve power dissipation during PWM operation.
5. Industry standard PHASE, I0, I1 logic inputs are used to control each full-bridge.
6. The outputs are protected from shorts between motor leads and short-to-ground events, which protect the driver and associated circuitry from thermal damage or flare-ups.
7. Other protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), crossover current and over-current protection. Special power-up sequencing is not required.

Package: 24 contact 4.0 mm × 4.0 mm × 0.75 mm QFN (ES) and a 24 lead 7.8 mm × 4.4 mm × 1.2 mm eTSSOP (LP) packages. Both packages have exposed thermal pads for enhanced thermal dissipation, and are lead (PB) free with 100% matte tin plated lead frames.

For more information visit: www.allegromicro.com