Introduction The AMIS?30521/NCV70521 is a micro?stepping stepper motor driver for bipolar stepper motors. The chip is connected through I/O pins and a SPI interface with an external microcontroller. The AMIS?30521/NCV70521 contains a current?translation table. It takes the next micro?step depending on the clock signal on the “NXT” input pin and the status of the “DIR” （= direction） register or input pin. The chip provides a so?called “Speed and Load Angle” output. This allows the creation of stall detection algorithms and control loops based on load?angle to adjust torque and speed. It is using a proprietary PWM algorithm for reliable current control. The AMIS?30521/NCV70521 is implemented in I2T100 technology， enabling both high voltage analog circuitry and digital functionality on the same chip. The chip is fully compatible with the automotive voltage requirements. The 521 is ideally suited for general purpose stepper motor applications in the automotive， industrial， medical and marine environment. The AMIS?30521 is intended for use in industrial applications. The NCV70521 version is qualified for use in automotive applications.