The A4983 is a complete oneMicrostepping motor driver, with a built-in converter for easy operation. It operates bipolar stepper motors in full, half, 1/4, 1/8 and 1/16 step modes with output drive performance up to 35 V and ±2 amps. The A4983 includes a fixed off-timeCurrent regulator, the regulator can operate in slow or mixed attenuation mode.
The converter is key to the A4983'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 A4983 interface is ideal for complex applications where microprocessors are unavailable or overloaded.
The chopper control within the A4983 automatically selects the current decay mode (slow or mixed). When a signal appears at the Step input pin, the A4983 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 31.25% of the period reaching a fixed off-time, and then set the cut-off remaining period to slow decay.) This current attenuation control scheme reduces audible motor noise, increases step accuracy, and reduces power dissipation.
Internal synchronous rectification control circuitry reduces power dissipation 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 A4983 is available in a 5 mm × 5 mm × 0.90 nominal surface-mount QFN package with an exposed heat transfer spacer (suffix ET). The package is lead (suffix –T) and features 100% matte tin leadframe plating.
- Low RDS(ON)output
- Self-drive current attenuation mode detection/selection
- Mixed with slow current attenuation modes
- Synchronous rectification for low power dissipation
- Internal UVLO
- Crossover current protection
- 3.3 and 5 V compatible logic supplies
- Ultra-thin QFN package
- Thermal shutdown circuit