1. Overview

️· What it is: The HM2602 is a motor driver IC, designed primarily for controlling fan motors in applications like computer cooling, ventilation, and similar uses.
️· Key Features:
- Speed Control (PWM)
- Lock Protection (Automatic Restart)
- Over-Current Protection (OCP)
- Under-Voltage Lockout (UVLO)
- Thermal Shutdown (TSD)
- Soft Switch Function (reduces electromagnetic noise)
- Suitable for both 12V and 24V applications (though SMIN functionality has limitations with 24V)

2. Operating Modes & Functions

️· Speed Control (PWM):
- Full Speed: 100% PWM duty cycle.
- Variable Speed: Adjustable duty cycle, with minimum duty cycle determined by the SMIN pin (equation: _Minimum_ _ _duty_ _ _cycle_ = 0.305* _VCC_ − _V_ _SMIN_).
- Minimum Speed: Controlled by SMIN pin.
️· Lock Protection: Detects rotor blockage, shuts down output, and attempts restart every 4 seconds.
️· Over-Current Protection (OCP): Shuts down the driver if current exceeds a limit, then restarts every 4 seconds.
️· Under-Voltage Lockout (UVLO): Disables circuitry and resets if VREG6 falls below 3.5V.
️· Thermal Shutdown (TSD): Shuts down PWM if the junction temperature reaches a threshold, with hysteresis of 15°C.
️· Soft Switch: Reduces electromagnetic noise by smoothing current changes during commutation.

3. Application Circuit Considerations

️· Power and Ground: F-GND and VSS *must* be connected together on the PCB.
️· Bypass Capacitor & TVS Diode: Needed for stability and surge protection.
️· Hall Input: Requires a signal level of at least 120mV p-p.
️· FG Output: An open-collector output that should be left unconnected if not used.
️· HB Pin: Provides a constant voltage for Hall sensor biasing.
️· SMIN Pin: Sets minimum speed – important: only for 12V applications. For 24V, connect a 1M resistor to VCC.
️· Motor Capacitor: Optional, to reduce noise.
️· Schottky Diode: Recommended for larger currents.
️· Zener Diode: Recommended for regenerative current routing.

4. Voltage Support

️· 12V Operation: Supports standard functionality.
️· 24V Operation: Compatible, but the SMIN pin for minimum speed control is limited. It is advisable to connect a 1M ohm resistor to VCC to allow for stable operation.

5. Package Dimensions

️· Datasheet includes dimension parameters for the HTSSOP14 and TSSOP-20 packages.

Summary Table of Key Parameters & Limitations

Feature	Value/Description
Operating Voltage	12V and 24V (with SMIN limitations at 24V)
PWM Frequency	21kHz - 28kHz
SMIN Function	12V Only (use 1M resistor for 24V)
Minimum Speed Control	SMIN Pin (Equation provided in Datasheet)
Overcurrent Protection	Automatic Restart (4-second intervals)
Thermal Shutdown Hysteresis	~15°C
UVLO Voltage	3.5V

This detailed breakdown should help you understand the HM2602's capabilities, limitations, and important design considerations.