MICROSTEPPING DMOS DRIVER WITH TRANSLATOR

The A3977xED and A3977xLP are complete microstepping motor drivers with built-in translator. They are designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 35 V and ±2.5 A. The A3977 includes a fixed off-time current regulator that has the ability to operate in slow-, fast-, or mixed-decay modes. This currentdecay 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 A3977. By simply inputting one pulse on the STEP input the motor will take one step (full, half, quarter, or eighth depending on two logic inputs). There are no phase-sequence tables, high-frequency control lines, or complex interfaces to program. The A3977 interface is an ideal fit for applications where a complex µP is unavailable or over-burdened.

FEATURES

■ ±2.5 A, 35 V Output Rating

■ Low rDS(on) Outputs, 0.45 Ω Source, 0.36 Ω Sink Typical

■ Automatic Current Decay Mode Detection/Selection

■ 3.0 V to 5.5 V Logic Supply Voltage Range

■ Mixed, Fast, and Slow Current Decay Modes

■ Home Output

■ Synchronous Rectification for Low Power Dissipation

■ Internal UVLO and Thermal Shutdown Circuitry

■ Crossover-Current Protection