A3977: Microstepping DMOS Driver with Translator

Description

The A3977 is a complete microstepping motor driver, with built-in translator. It is designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 35 V and ±2.5 A. The A3977 includes a fixed off-time current regulator that has the ability to operate in slow-, fast-, or mixed-decay modes. This current-decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation.

The translator is the key to the easy implementation of the A3977. Simply inputting one pulse on the STEP input drives the motor one step (two logic inputs determine if it is a full-, half-, quarter-, or eighth-step). There are no phase-sequence tables, high-frequency control lines, or complex interfaces to program. The A3977 interface is an ideal fit for applications where a complex microprocessor is unavailable or 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-up sequencing is not required.

The A3977 is supplied in a thin (<1.2 mm) 28-pin TSSOP with exposed thermal pad (suffix LP). The A3977 is lead (Pb) free with 100% matte tin leadframe plating.

Top Features

  • ±2.5 A, 35 V output rating
  • Low rDS(ON) outputs, 0.45 Ω source, 0.36 Ω sink typical
  • Automatic current decay mode detection/selection
  • 3.0 to 5.5 V logic supply voltage range
  • Mixed, fast, and slow current decay modes
  • Home output
  • Synchronous rectification for low power dissipation
  • Internal UVLO and thermal-shutdown circuitry
  • Crossover-current protection

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A3977SLPTR-T 28-lead TSSOP -20°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

Packaging

The A3977 is supplied in a thin (<1.2 mm) 28-pin TSSOP with exposed thermal pad (suffix LP). The A3977 is lead (Pb) free, with 100% matte tin leadframe plating.

Package:

Package LP, 28-Pin TSSOP
with exposed thermal pad

Allegro LP 28 Package Image

Design Support Tools

Frequently Asked Questions

A3977 FAQ