A4988SETTR-T

A4988 DMOS Microstepping Driver with Translator And Overcurrent Protection Features and Benefits ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ Low RDS(ON) outputs Automatic current decay mode detection/selection Mixed and Slow current decay modes Synchronous rectification for low power dissipation Internal UVLO Crossover-current protection 3.3 and 5 V compatible logic supply Thermal shutdown circuitry Short-to-ground protection Shorted load protection Five selectable step modes: full, 1/2, 1/4, 1/8, and 1/16 Package: 28-contact QFN Description The A4988 is a complete microstepping motor driver with built-in translator for easy operation. It is designed to operate bipolar stepper motors in full-, half-, quarter-, eighth-, and sixteenth-step modes, with an output drive capacity of up to 35 V and ±2 A. The A4988 includes a fixed off-time current regulator which has the ability to operate in Slow or Mixed decay modes. The translator is the key to the easy implementation of the A4988. 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 A4988 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. During stepping operation, the chopping control in the A4988 automatically selects the current decay mode, Slow or Mixed. In Mixed decay mode, the device is set initially to a fast decay 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. with exposed thermal pad 5 mm × 5 mm × 0.90 mm (ET package) Continued on the next page… Approximate size Typical Application Diagram VDD 0.1 µF VREG ROSC 0.22 µF 0.1 µF 0.22 µF CP1 CP2 VCP VDD VBB2 5 kΩ Microcontroller or Controller Logic SLEEP STEP VBB1 OUT1A A4988 OUT1B SENSE1 MS1 MS2 MS3 OUT2A DIR OUT2B ENABLE SENSE2 RESET VREF 4988-DS, Rev. 5 GND GND 100 µF DMOS Microstepping Driver with Translator And Overcurrent Protection A4988 Description (continued) 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 A4988 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. Selection Guide Part Number A4988SETTR-T Package Packing 28-contact QFN with exposed thermal pad 1500 pieces per 7-in. reel Absolute Maximum Ratings Characteristic Symbol Load Supply Voltage VBB Notes Rating Units 35 V Output Current IOUT ±2 A Logic Input Voltage VIN –0.3 to 5.5 V Logic Supply Voltage VDD –0.3 to 5.5 V –2.0 to 37 V VSENSE –0.5 to 0.5 V VREF 5.5 V –20 to 85 ºC TJ(max) 150 ºC Tstg –55 to 150 ºC Motor Outputs Voltage Sense Voltage Reference Voltage Operating Ambient Temperature Maximum Junction Storage Temperature TA Range S Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 DMOS Microstepping Driver with Translator And Overcurrent Protection A4988 Functional Block Diagram 0.1 µF 0.22 µF VREG VDD Current Regulator ROSC CP1 CP2 Charge Pump OSC VCP 0.1 µF DMOS Full Bridge REF DAC VBB1 OUT1A OUT1B PWM Latch Blanking Mixed Decay STEP OCP Gate Drive DIR RESET MS1 Translator Control Logic MS2 PWM Latch Blanking Mixed Decay ENABLE SLEEP DAC DMOS Full Bridge VBB2 RS1 OUT2A OCP MS3 SENSE1 OUT2B SENSE2 RS2 VREF Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A4988 DMOS Microstepping Driver with Translator And Overcurrent Protection ELECTRICAL CHARACTERISTICS1 at TA = 25°C, VBB = 35 V (unless otherwise noted) Characteristics Output Drivers Load Supply Voltage Range Logic Supply Voltage Range Output On Resistance Min. Typ.2 Max. Units 8 3.0 – – – – – – – – – – 320 320 – – – – – – 35 5.5 430 430 1.2 1.2 4 2 8 5 V V mΩ mΩ V V mA mA mA mA VIN(1) VDD×0.7 – – V VIN(0) – – V –20