G9941 Linear 12V DC Fan Driver IC SOP-8

G9941 Linear 12V DC Fan Driver SOP-8 is a high-efficiency, integrated solution designed specifically for driving DC brushless fans in noise-sensitive environments. This sophisticated IC provides a linear output voltage that precisely corresponds to the input control signal, allowing for smooth speed transitions without the audible switching noise often associated with PWM-based drivers. Consequently, the G9941 excels in thermal management systems where acoustic comfort is a priority. Furthermore, the device incorporates advanced protection features, including locked rotor shutdown and automatic restart functions, to ensure long-term system reliability. Therefore, designers can implement this compact SOP-8 driver to achieve a perfect balance between cooling performance and silent operation in modern electronic hardware.

Key Features:

• Linear Speed Control: The driver delivers a linear voltage output to the fan motor, eliminating the electromagnetic interference and acoustic hum typical of high-frequency switching.
• Locked Rotor Protection: This internal safety mechanism detects when the fan blades are obstructed and automatically cuts power to prevent coil overheating.
• Auto-Restart Function: After a detected fault or stall, the IC periodically attempts to restart the fan motor once the obstruction is cleared.
• Low Saturation Voltage: The G9941 features a low dropout voltage, which maximizes the maximum reachable fan speed even when operating near the supply rail.
• Built-in Thermal Shutdown: An integrated temperature sensor protects the IC itself by disabling the output if the silicon temperature exceeds safe limits.

Technical Specifications:

• Operating Supply Voltage (V_CC): 3.5 V to 18 V
• Maximum Output Current: 500 mA (Continuous)
• Quiescent Current: ≈ 4 mA
• Output Saturation Voltage: ≤ 0.6 V at 200 mA
• Thermal Shutdown Temperature: +150°C
• Operating Temperature Range: −40°C to +85°C

Mechanical Specifications:

• Package Type: SOP-8 (Small Outline Package)
• Mounting Style: Surface Mount Device (SMD)
• Lead Material: Tinned Copper Lead-frame
• Encapsulation: Molded Plastic (Epoxy)

Dimensions:

• Body Length: ≈ 4.90 mm
• Body Width (excluding leads): ≈ 3.90 mm
• Total Width (including leads): ≈ 6.00 mm
• Body Height: ≈ 1.50 mm
• Lead Pitch: 1.27 mm

Pinout and Wiring:

• Pin 1 (V_OUT): Output pin connected to the positive terminal of the DC fan motor.
• Pin 2 (GND): Common ground connection for the power and control sections.
• Pin 3 (CTL): Control input pin where an analog voltage or filtered PWM signal determines the fan speed.
• Pin 4 (V_CC): Main power supply input, typically connected to 12 V.
• Pins 5-8 (NC/GND): These pins often serve as additional ground paths or heat-sinking connections depending on the specific PCB layout.
• Wiring Note: However, always place a decoupling capacitor close to the V_CC pin to filter out motor-induced supply noise.

Datasheet Reference:

• Download Global Mixed-mode Technology G9941 Datasheet

Commonly Used in:

• Computing Hardware: Managing the cooling fans in laptops, desktop power supplies, and workstation chassis.
• Projectors and Displays: Driving internal cooling systems where fan noise would interfere with audio or user experience.
• Network Equipment: Regulating airflow in routers and switches to maintain optimal operating temperatures.

Applications:

• Quiet Cooling: Ideal for home theater PCs (HTPC) and studio equipment requiring silent thermal regulation.
• Variable Speed Control: Perfect for systems that adjust fan RPM based on real-time temperature sensor data.
• Industrial Cabinets: Providing reliable motor driving with built-in protection against mechanical stalls.

Equivalent Models:

• Microchip TC648: A similar integrated fan speed controller that utilizes PWM to DC conversion for linear driving.
• Diodes Inc. AH2984: An alternative motor driver IC, however, it may require different external component values for speed matching.
• GMT G9942: A related family member from the same manufacturer offering similar characteristics in different package variations.

Package Includes:

• 1 x G9941 Linear 12V DC Fan Driver SOP-8