CYPD3174-16SXQ is targeted at Opto Coupler Feedback applications with a Opto Coupler Feedback Bootloader. It has a reduced pin list compared to CYPD3171 and CYPD3175.
It could also be used in directed feedback application with a modified hardware and firmware.
The schematic is shown below:
The firmware is derived from the CYPD3175-24LQXQ_pa_direct_fb with minor modifications. The only things changed are the device part number of bootloader and the project.