I2C Fan Speed Controller with 4 High-Side Pre-Drivers
The Analog Devices MAX6620ATI+T is a dedicated fan speed controller that uses an I2C interface to manage up to four brushed DC fans. It integrates four high-side pre-drivers, meaning it handles the logic and gate drive for external N-channel MOSFETs rather than switching the motor current directly. This architecture keeps the heat dissipation off the controller and lets you scale the fan current by choosing the external FETs. The part operates from a 3V to 5.5V supply, which aligns with common 3.3V and 5V system rails found in telecom, server, and industrial equipment. The -40°C to 125°C temperature range covers forced-air environments inside enclosures where ambient can climb well above 85°C.
28-TQFN Package and Layout Considerations
Housed in a 28-TQFN (5x5 mm) package with an exposed pad, the MAX6620ATI+T requires a thermal via pattern under the paddle to pull heat into the PCB ground plane. The exposed pad is the primary thermal path — without a good solder joint to the pad, junction temperature rises quickly under continuous operation. The 28-WFQFN case footprint is standard; the datasheet layout recommendation shows a 0.5 mm pitch with the pad centered.
Active Lifecycle — No Obsolescence Risk
The MAX6620ATI+T carries an Active product status with ROHS3 compliance. There is no last-time-buy notice or NRND flag, so it is safe to qualify into a new BOM without near-term redesign risk.