I2C fan speed controller for four independent channels
The MAX6620ATI+ from Analog Devices (formerly Maxim Integrated) is a dedicated fan speed controller that manages up to four brushed DC fans via an I2C interface. It outputs four high-side pre-driver signals to drive external N-channel MOSFETs, giving the system designer control over fan voltage and speed without burdening the main MCU with PWM generation or tachometer polling.
Four high-side pre-drivers — what that means for the BOM
The four pre-driver outputs are high-side only, meaning each channel drives the gate of an external N-channel MOSFET that switches the fan's positive supply rail. The controller handles the closed-loop speed regulation and tachometer feedback decoding internally, so the external BOM per fan is just one MOSFET plus a few passives — no separate PWM generator or op-amp for tach signal conditioning. Pre-driver outputs drive external N-channel MOSFETs.
Package and mounting
Housed in a 28-TQFN (5x5 mm) package with an exposed pad, the MAX6620ATI+ requires a surface-mount reflow process. The exposed pad must be soldered to a thermal land on the PCB for adequate heat dissipation — the part can draw enough current through the pre-driver outputs to need that thermal path, especially at the high end of the temperature range.
Lifecycle and supply position
The MAX6620ATI+ carries an active lifecycle status and is ROHS3 compliant. Sourced through independent distribution, this part is available to order against an RFQ.