[ This Figure , near callout 10]
The ZCU111 cooling fan connector is shown in This Figure .
The ZCU111 uses the Infineon MAX6643 (U52) fan controller, which autonomously controls the fan speed by controlling the pulse width modulation (PWM) signal to the fan based on the die temperature sensed via the FPGA's DXP and DXN pins. The fan rotates slowly (acoustically quiet) when the RFSoC is cool and rotates faster as the FPGA heats up (acoustically noisy).
The fan speed (PWM) versus the RFSoC die temperature algorithm along with the over temperature set point and fan failure alarm mechanisms are defined by the strapping resistors on the MAX6643 device. The over temperature and fan failures alarms can be monitored by any available processor in the RFSoC by polling the I2C expander U22 on the I2C0 bus. See the MAX6643 [Ref 25] data sheet for more information on the device circuit implementation on this board.
Note: At initial power on, it is normal for the fan controller to energize at full speed for a few seconds.