The A3982 by ALLEGRO microsystems is a sophisticated device tailored for driving bipolar stepper motors utilizing a built-in translator designed to facilitate easy operation. Targeted at full- and half-step modes, the driver can manage up to 35 V and +2 A, accommodating a range of stepper motor applications. Notable features include low RDS(on) outputs, automatic detection and selection for current decay mode, and the choice of Mixed or Slow current decay modes. Moreover, it comes with built-in synchronous rectification to minimize power dissipation.
Key Features and Advantages
The datasheet highlights the primary features of A3982 which ensures its optimal performance and versatility in various applications. These features include low RDS(on) outputs, automatic selection between Mixed and Slow current decay modes, synchronous rectification for efficient power usage, and internal under-voltage lockout (UVLO) and thermal shutdown circuitries. This ensures protection against crossover-current, and no specific power-on sequencing is necessary, simplifying the design and usage.
Simple Operation and Control
One of the most significant attributes of the A3982 is its straightforward operation enabled by the translator. This translates to a lack of necessity for phase sequence tables, high-frequency control lines, or complex interfaces. A mere single pulse to the STEP input is enough to drive the stepper motor one step further, making it a prime option for systems where a microprocessor is not present or cannot be dedicated to motor control.
Current Decay Control Scheme
The driver automatically determines the appropriate current decay mode based on the motor phase current requirements, enabling a reduction in audible motor noise, increased step accuracy, and reduced power dissipation. The automatic selection of current decay mode, whether the need is for higher or lower current, greatly enhances the performance and reliability of the stepper motor operations.
Protection Mechanisms
Integrated circuit protection is a critical aspect of the A3982, which encompasses thermal shutdown with hysteresis, crossover-current protection, and UVLO. These protections contribute to a reliable operation of the motor driver without necessitating special power-on sequences. Additionally, the device is equipped with an internal synchronous rectification control circuitry that further improves power dissipation, particularly during PWM operation.
Packaging and Thermal Dissipation
The chip comes in a thermally-efficient 24-pin wide-body SOIC package with internally fused leads to increase heat dissipation. The package is environmentally conscious, being lead (Pb) free and 100% matte tin-plated on its leadframe.
Regulatory Information and Selection Guide
In addition to the detailed application specifications, the datasheet provides selection guidance and part number information for varied packaging options. Absolute maximum ratings are clearly stated, which includes load supply voltage, logic input voltage, sense voltage, and reference voltage along with the output current, and operational as well as storage temperature ranges.
Contact and Manufacturer Information
For additional information and packing options, customers are directed to contact Allegro MicroSystems, whose address and website are provided, ensuring purchaser support and further engagement.
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