The A3983 is a complete oneMicrostepping motor driver, with a built-in converter for easy operation. It operates bipolar stepper motors in full, half, 1/4 and 1/8 step modes with output drive performance up to 35 V and ±2 A. The A3983 includes a fixed off-time current regulator that can operate in slow or mixed decay mode.
The converter is key to the A3983's ease of implementation. Simply enter a pulse into the "step" input to drive the motor to generate microsteps. There are no phase order tables, high-frequency control lines, or complex interfaces in this program. The A3983 interface is ideal for applications where complex microprocessors are unavailable or overloaded.
The chopper control within the A3983 automatically selects the current decay mode (slow or mixed). When a signal appears at the Step input pin, the A3983 determines whether the step will produce a higher or lower current in each motor phase. If the charge generates a higher current, set this decay mode to "slow" decay. If the charge produces a lower current, the current decay is set to mixed (start with fast decay for cycles reaching 31.25% of fixed downtime, then set to slow decay until the remaining period. This current attenuation control scheme reduces audible motor noise, increases step accuracy, and reduces power dissipation.
Internal synchronous rectification control circuitry is used to improve power consumption during pulse-width modulation (PWM) operation. Internal circuit protection includes thermal shutdown due to hysteresis, undervoltage lockout (UVLO), and crossover current protection. No special power-up sequencing is required.
The A3983 is available in a low profile (maximum height: 1.2 mm) 24-pin TSSOP package with exposed heat shield plate (suffix: LP). The package is lead (Pb) free and features 100% matte tin leadframe plating.
- Low RDS (On)output
- Automatic detection/selection of current decay mode
- Mixed with slow current attenuation modes
- Synchronous rectification for low power dissipation
- Internal undervoltage lockout (UVLO) and thermal shutdown circuitry
- Crossover current protection