Description
The A3977 is a complete microstepping motor driver with built-in translator. It is designed for the operation of bipolar stepper motors
Stepper motors in full, half, quarter and eighth step operation with an output voltage of 35 V and ±2.5 A. The A3977 contains a current controller with a fixed switch-off time, which can operate in slow, fast or mixed decay mode. This current decay control
reduces audible motor noise, increases step accuracy and reduces power loss.
The translator is the key to the simple implementation of the A3977.
Key features
- ±2.5 A, 35 V output power
- Low RDS(on) output, 0.28 Ù source, 0.22 Ù sink typical
- Automatic detection/selection of current drop-out mode
- 3.0 to 5.5 V logic supply voltage range
- Mixed fast and slow current sink modes
- Home output
- Synchronous rectification for low power dissipation
- Internal UVLO and thermal shutdown circuitry
- Crossover current protection
The simple input of a pulse at the STEP input drives the motor one step (two logic inputs determine whether it is a full, half, quarter or eighth step),
quarter or eighth step). There are no phase sequence tables, high frequency control lines or complex interfaces to program.
The A3977 interface is ideal for applications where a complex microprocessor is unavailable or overloaded.
An internal synchronous rectifier control circuit is provided to improve power dissipation during PWM operation.
Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout (UVLO) and overcurrent protection.
protection. No special power-up sequencing is required.
