AMT49700 Automotive Stepper Motor Driver IC

By Allegro MicroSystems, LLC 61

AMT49700 Automotive Stepper Motor Driver IC

Allegro's AMT49700 is a flexible microstepping stepper motor driver with integrated phase current control, built-in translator, and simple motion control. As a single chip solution, it is designed to operate bipolar stepper motors in full, half, quarter, eighth, and sixteenth step modes at up to 28 V.

Reducing the microprocessor overhead, the AMT49700 is a unique motion profile controller that provides programmable motor acceleration and deceleration which is particularly useful for systems with multiple stepper motors. Additionally, it provides integrated current sensing, which also reduces the number of external components.

Ideal for high-temperature applications such as headlamp leveling/bending and engine management motion control, the AMT49700 is versatile in that it is also suitable for other automotive stepper applications such as HVAC flap and valves.

The current regulator operates with fixed frequency PWM and uses adaptive mixed current decay to reduce audible motor noise and increase step accuracy. The current in each phase of the motor is controlled through a DMOS full-bridge using synchronous rectification to improve power dissipation. Internal circuits and timers prevent cross-conduction and shoot through when switching between high-side and low-side drives.

The outputs are protected from short circuits, and features for low load current detection are included. Chip-level protection includes hot thermal warning, overtemperature shutdown, overvoltage lockout, and undervoltage lockout.

The AMT49700 is supplied in a 32-terminal 5 mm x 5 mm QFN package with an exposed thermal pad (package type ET).

Features and Benefits
  • Peak motor current up to 1.6 A at 28 V
  • Low RDS(ON) outputs, 0.5 Ω source and sink typical
  • Continuous operation at high ambient temperature
  • 3.7 V to 42 V supply operation
  • Adaptive mixed current decay
  • Synchronous rectification for low power dissipation
  • Output slew control and PWM frequency spreading for EMC noise reduction
  • Internal overvoltage and undervoltage lockout
  • Hot warning and overtemperature shutdown
  • Short-circuit, open-load diagnostics
  • Programmable motion control
  • Configurable through serial interface
  • Simple step and direction control option
  • Automotive stepper motors
  • Engine management
  • Headlamp positioning
  • HVAC flap and valve control

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