The A3979 is a complete microstepping motor driver with built-in translator, designed as a pin-compatible replacement for the successful A3977, with enhanced microstepping (1/16 step) precision. It is designed to operate bipolar stepper motors in full-, half-, quarter-, and sixteenth- step modes, with an output drive capacity of up to 35 V and ±2.5 A. The A3979 includes a fixed off-time current regulator that has the ability to operate in Slow, Fast, or Mixed decay modes. This current-decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The translator is the key to the easy implementation of the A3979. It allows the simple input of one pulse on the STEP pin to drive the motor one microstep, which can be either a full step, half, quarter, or sixteenth, depending on the setting of the MS1 and MS2 logic inputs. There are no phase-sequence tables, high-frequency control lines, or complex inter- faces to program. The A3979 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. Internal synchronous-rectification control circuitry is provided to improve power dissipation during PWM operation. Internal circuit protection includes: thermal shutdown with hysteresis, UVLO (under- voltage lockout), and crossover-current protection. Special power-on sequencing is not required. The A3979 is supplied in a low-profile
The A3979 is a complete microstepping motor driver featuring a built-in translator that simplifies implementation by allowing single-pulse input control for full, half, quarter, or sixteenth-step modes. It serves as a pin-compatible replacement for the A3977 with enhanced precision and includes features like automatic current decay mode detection and internal synchronous rectification to reduce power dissipation.
| Output Current Rating | +2.5 A, 35 V output rating |
|---|---|
| Logic Supply Voltage Range | 3.0 to 5.5 V |
| Microstep Resolution | 1/16 step precision |
| Package Type | 28-pin TSSOP with Exposed Thermal Pad |
The device supports full step, half step, quarter step, and sixteenth-step modes.
No, special power-on sequencing is not required for this device.