Introduction
The AMIS−30511 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−30511 contains a current−translation table and 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, step loss detection, and control loops based on load−angle to adjust torque and speed. It is using a proprietary PWM algorithm for reliable current control.

KEY FEATUREs
• Dual H−Bridge for 2−phase Stepper Motors
• Programmable Peak−current up to 800 mA Using a 5−bit Current DAC
• On−chip Current Translator
• SPI Interface
• Speed and Load Angle Output
• Seven Step Modes from Full−step up to 32 Micro−steps
• Fully Integrated Current−sense
• PWM Current Control with Automatic Selection of Fast and Slow Decay
• Low EMC PWM with Selectable Voltage Slopes
• Active Fly−back Diodes
• Full Output Protection and Diagnosis
• Thermal Warning and Shutdown
• Compatible with 3.3 V Microcontrollers, 5 V Tolerant Inputs
• −40°C to 125°C Temperature Range at 800 mA Peak Current