The A3957SA and A3957SLB are designed for driving one winding of a bipolar stepper motor in a microstepping mode. The outputs are rated for continuous output currents to 1.5 A and operating voltages to 50 V. Internal pulse-width modulated (PWM) current control combined with an internal four-bit nonlinear digital-to-analog converter allows the motor current to be controlled in full-, half-, quarter-, eighth-, or sixteenth-step (microstepping) modes. Nonlinear increments minimize the number of control lines necessary for microstepping. Microstepping provides for increased step resolution, and reduces torque variations and resonance problems at low speed.