A3982 DMOS Stepper Motor Driver with Translator Features and Benefits Description Low R outputs The A3982 is a complete stepper motor driver with built- DS(on) Automatic current decay mode detection/selection in translator for easy operation. It is designed to operate Mixed and Slow current decay modes bipolar stepper motors in full- and half-step modes, with an Synchronous rectification for low power dissipation output drive capacity of up to 35 V and 2 A. The A3982 Internal UVLO and thermal shutdown circuitry includes a fixed off-time current regulator which has the Crossover-current protection ability to operate in Slow or Mixed decay modes. The translator is the key to the easy implementation of the A3982. Simply inputting one pulse on the STEP input drives the motor one step. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. The A3982 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. The chopping control in the A3982 automatically selects the current decay mode (Slow or Mixed). When a signal Package: 24 pin SOICW with internally occurs at the STEP input pin, the A3982 determines if fused leads (suffix LB) that step results in a higher or lower current in each of the motor phases. If the change is to a higher current, then the decay mode is set to Slow decay. If the change is to a lower current, then the current decay is set to Mixed (set initially to a fast decay for a period amounting to 31.25% of the Continued on the next page Not to scale Pin-out Diagram OUT1A OUT2A 1 24 SENSE1 SENSE2 2 23 VBB2 VBB1 3 22 OUT2B OUT1B 4 21 ENABLE DIR 5 20 PGND PGND 6 19 PGND PGND 7 18 CP1 REF 8 17 CP2 STEP 9 16 VCP 10 15 VDD VREG 11 14 ROSC MS1 RESET 12 13 26184.28C Charge Reg Pump Translator & Control Logic OSC A3982 DMOS Stepper Motor Driver with Translator Description (continued) Internal circuit protection includes: thermal shutdown with fixed off-time, then to a slow decay for the remainder of the hysteresis, undervoltage lockout (UVLO), and crossover-current off-time). This current decay control scheme results in reduced protection. Special power-on sequencing is not required. audible motor noise, increased step accuracy, and reduced power The A3982 is supplied in a 24-pin wide-body SOIC dissipation. (package LB) with internally-fused power ground leads for Internal synchronous rectification control circuitry is provided to enhanced thermal dissipation. It is lead (Pb) free, with 100% improve power dissipation during PWM operation. matte tin plated leadframe. Selection Guide Part Number Packing* Package A3982SLB-T 31 pieces per tube 24-pin Wide SOIC with pins 6 and 7, and 18 and 19, fused internally A3982SLBTR-T 1000 pieces per reel *Contact Allegro for additional packing options Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Load Supply Voltage V 35 V BB Logic Input Voltage V 0.3 to 7 V IN Sense Voltage V 0.5 V SENSE Reference Voltage V 4V REF Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under Output Current I 2 A OUT any set of conditions, do not exceed the specified current rating or a junction temperature of 150C. Operating Ambient Temperature T Range S 20 to 85 C A Maximum Junction Temperature T (max) 150 C J Storage Temperature T 55 to 150 C stg Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com