1. Overview

The MPS MP6601 is a stepper motor driver IC designed to drive two stepper motors (or can be used to drive two DC motors). It provides features like current regulation, automatic decay mode, over-voltage/current/temperature protection, and sleep mode for power saving. It's intended for applications requiring controlled and efficient stepper motor operation.

2. Key Features:

️· Dual-Driver: Can drive two stepper motors simultaneously or be configured to drive two DC brush motors.
️· Current Regulation: Programmable current regulation allows precise control of motor torque and prevents overheating.
️· Automatic Decay Mode: Automatically switches between slow and fast decay modes to optimize current regulation based on operating conditions.
️· Protections:
- Over-Voltage Protection (OVP): Shuts down if input voltage exceeds a threshold (38V).
- Over-Current Protection (OCP): Limits current to prevent damage.
- Over-Temperature Protection (OTP): Reduces power if the die gets too hot.
- UVLO (Under-Voltage Lockout): Prevents operation if input voltage is too low.
️· Sleep Mode: Reduces power consumption when the motor isn't actively being used.
️· Programmable Off-Time: Adjustable constant off-time allows tuning of current regulation.
️· Blanking Time: Prevents errant shutdowns due to transient current spikes.
️· Programmable Current Sensing: Allows adjustment of the current limit using external resistors (ISET).

3. Operation

️· Current Regulation: The current in the motor winding is regulated based on the values of external resistors (ISET). The formula for maximum current is: `I Max = 71kΩ / R ISET`.
️· Automatic Decay Modes:
- Slow Decay: Default mode, used for regulation unless a fast decay is needed.
- Fast Decay: Used when current needs to be reduced rapidly (e.g., for quick reversals or low inductance motors).
️· Sleep Mode: nSLEEP pin needs to be active low and at least 1ms of settling time is needed before issuing a step command when waking up.
️· Fault Handling: nFAULT pin indicates fault conditions (OCP, OTP, OVP), requiring an external pull-up resistor to monitor.

4. Applications

️· Stepper Motor Drives: Primarily designed for precise stepper motor control in applications such as:
- Robotics
- Printers
- Industrial Automation
️· DC Brush Motor Drives: Can be used as a dual DC motor driver.
- Requires attention to current limiting.
- Does not support short brake functionality.

5. Key Takeaways & Considerations:

️· Thermal Management is Crucial: Proper PCB layout with a good thermal path is essential for dissipating heat from the IC, especially when driving motors at higher currents. The exposed pad must be connected to a large copper area.
️· Component Selection: Pay close attention to the selection of external components like ISET and ROSC resistors to achieve desired motor performance and current limits.
️· Sequencing is Important: Ensure proper sequencing when waking up from sleep mode.
️· DC Motor Limitations: When used with DC motors, be aware of the limitations regarding braking and the need for careful current limiting.
️· Datasheet is a Guide: This summary provides an overview, and the complete datasheet should be referred to for detailed specifications and application information.