A3977 Microstepping DMOS Driver with Translator FEATURES AND BENEFITS DESCRIPTION 2.5 A, 35 V output rating The A3977 is a complete microstepping motor driver, with Low R outputs, 0.28 source, 0.22 sink typical built-in translator. It is designed to operate bipolar stepper DS(on) Automatic current decay mode detection/selection motors in full-, half-, quarter-, and eighth-step modes, with 3.0 to 5.5 V logic supply voltage range output drive capability of 35 V and 2.5 A. The A3977 includes Mixed, fast, and slow current decay modes a fixed off-time current regulator that has the ability to operate in Home output slow-, fast-, or mixed-decay modes. This current-decay control Synchronous rectification for low power dissipation scheme results in reduced audible motor noise, increased step Internal UVLO and thermal shutdown circuitry accuracy, and reduced power dissipation. Crossover-current protection 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. Package: 28-pin TSSOP (suffix LP) with The A3977 interface is an ideal fit for applications where a Exposed Thermal Pad complex microprocessor is unavailable or over-burdened. 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 an exposed thermal pad (suffix LP). The A3977 is a lead Not to scale (Pb) free, with 100% matte tin leadframe plating. Pin-out Diagram A3977-DS, Rev. 12A3977 Microstepping DMOS Driver with Translator SPECIFICATIONS Selection Guide Ambient Temperature, T A Part Number Packing Package (C) A3977SLPTR-T 4000 per reel 28-pin TSSOP 20 to 85 Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Load Supply Voltage V 35 V BB Logic Supply Voltage V 7.0 V DD Pulsed, t > 30 ns 0.3 to V + 0.3 V w DD Logic Input Voltage Range V IN Pulsed, t < 30 ns 1.0 to V + 1 V w DD Reference Voltage V V V REF DD Sense Voltage (DC) V 0.5 V SENSE Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, Output Current I 2.5 A OUT do not exceed the specified current rating or a junction temperature of 150C. Range K 40 to 125 C Operating Ambient Temperature T A Range S 20 to 85 C Maximum Junction Temperature T (max) 150 C J Storage Temperature T 55 to 150 C stg Thermal Characteristics Characteristic Symbol Test Conditions* Value Units Package Thermal Resistance R Package LP, on 4-layer PCB based on JEDEC standard 28 C/W JA *Additional thermal information available on the Allegro website. Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com