A5985: DMOS Microstepping Driver with Translator and Overcurrent Protection

The A5985 is a complete microstepping motor driver with built-in translator for easy operation. It is designed to operate bipolar stepper motors from full-step up to 1/32 step modes. Step modes are selectable by MSx logic inputs. It has an output drive capacity of up to 40 V and ±2 A.

A5985 introduces a proprietary Adaptive Percent Fast Decay (APFD) algorithm to optimize the current waveform over a wide range of stepper speeds and stepper motor characteristics. APFD adjusts on-the-fly the amount of fast decay during a PWM cycle to keep current ripple at a low level over the various operating conditions. This adaptive feature improves performance of the system resulting in reduced audible motor noise, reduced vibration, and increased step accuracy.

The translator is the key to the easy implementation of the A5985. Simply inputting one pulse on the STEP input drives the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. The A5985 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened.

Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover-current protection. Special power-on sequencing is not required.

The A5985 is supplied in a surface-mount QFN package (ET), 5 mm × 5 mm, with a nominal overall package height of 0.90 mm and an exposed pad for enhanced thermal dissipation. It is lead (Pb) free (suffix –T), with 100% matte-tin-plated leadframes.


Astrorep Inc. (Allegro and Sanken Semiconductors, Sanken Power Supplies)
141 John Street, Suite 300
Babylon, NY 11702
Phone: (631)422-2500
Fax: (631)422-2504
Web: www.astrorepinc.com
Email: donna.tweedy@astrorepinc.com

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  • Features and BenefitsFeatures and Benefits
  • PackagingPackaging
  • Technical DocsTechnical Docs
  • NewsNews
  • Drop-in replacement for A4988
  • Proprietary Adaptive Percent Fast Decay option
  • Low RDS(on) outputs
  • Single supply
  • Microstepping up to 32 microsteps per full step
  • Full torque step modes
  • Short-to-ground protection
  • Shorted load protection
  • Short-to-battery protection
  • Fault output
  • Low current Sleep mode, < 10 μA
  • Thin profile QFN
  • Thermal shutdown circuitry
  • Synchronous rectification for low power dissipation
  • Internal UVLO
  • Crossover-current protection

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A5985-Product-Image A5985-Functional-Block-Diagram A5985-Typical-Application

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check
Distributor Stock
APEK5985SET-01-T DEMO BOARD -20°C to 85°C No -- Contact your
local sales rep
Check Stock
A5985GETTR-T 28-lead QFN -40°C to 105°C Yes View Data Contact your
local sales rep
Check Stock

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