A4988 DMOS Microstepping Driver with Translator And Overcurrent Protection Features and Benefits Description Low R outputs DS(ON) The A4988 is a complete microstepping motor driver with Automatic current decay mode detection/selection built-in translator for easy operation. It is designed to operate Mixed and Slow current decay modes bipolar stepper motors in full-, half-, quarter-, eighth-, and Synchronous rectification for low power dissipation sixteenth-step modes, with an output drive capacity of up to Internal UVLO 35 V and 2 A. The A4988 includes a fixed off-time current Crossover-current protection regulator which has the ability to operate in Slow or Mixed 3.3 and 5 V compatible logic supply decay modes. Thermal shutdown circuitry The translator is the key to the easy implementation of the Short-to-ground protection A4988. Simply inputting one pulse on the STEP input drives Shorted load protection the motor one microstep. There are no phase sequence tables, 1 1 1 1 Five selectable step modes: full, / , / , / , and / 2 4 8 16 high frequency control lines, or complex interfaces to program. Package: The A4988 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. 28-contact QFN During stepping operation, the chopping control in the A4988 with exposed thermal pad automatically selects the current decay mode, Slow or Mixed. 5 mm 5 mm 0.90 mm In Mixed decay mode, the device is set initially to a fast decay (ET package) for a proportion of the fixed off-time, then to a slow decay for the remainder of the off-time. Mixed decay current control results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. Continued on the next page Approximate size Typical Application Diagram V 0.1 F0.1 F DD 0.22 F VREG ROSC CP1 CP2 VCP VBB1 0.22 F VDD 100 F VBB2 5 k Microcontroller or SLEEP OUT1A Controller Logic A4988 OUT1B STEP SENSE1 MS1 MS2 MS3 OUT2A DIR OUT2B ENABLE SENSE2 RESET VREF GND GND 4988-DS, Rev. 2DMOS Microstepping Driver with Translator A4988 And Overcurrent Protection Description (continued) Internal synchronous rectification control circuitry is provided The A4988 is supplied in a surface mount QFN package (ES), 5 mm to improve power dissipation during PWM operation. Internal 5 mm, with a nominal overall package height of 0.90 mm and an circuit protection includes: thermal shutdown with hysteresis, exposed pad for enhanced thermal dissipation. It is lead (Pb) free undervoltage lockout (UVLO), and crossover-current protection. (suffix T), with 100% matte tin plated leadframes. Special power-on sequencing is not required. Selection Guide Part Number Package Packing A4988SETTR-T 28-contact QFN with exposed thermal pad 1500 pieces per 7-in. reel Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Load Supply Voltage V 35 V BB Output Current I 2 A OUT Logic Input Voltage V 0.3 to 5.5 V IN Logic Supply Voltage V 0.3 to 5.5 V DD VBBx to OUTx 35 V Sense Voltage V 0.5 V SENSE Reference Voltage V 5.5 V REF Operating Ambient Temperature T Range S 20 to 85 C A Maximum Junction T (max) 150 C J Storage Temperature T 55 to 150 C stg Allegro MicroSystems, Inc. 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com