66 MHz clock — read throughput and boot time
The 66 MHz SPI clock is the limiting factor for sustained read throughput. With Quad I/O, the effective data rate reaches about 33 MB/s in fast-read mode. This is adequate for most microcontroller code shadowing and FPGA configuration loads, but if your design needs faster boot or higher throughput, the FL-S series also offers 133 MHz variants such as the S25FL128SAGNFI011. The trade-off is a slightly higher cost and tighter timing margin on the PCB.
Active lifecycle — no EOL risk for new designs
The FL-S series is a mature, widely deployed family with long-term supply commitment from Infineon.
Package and footprint — 8-WSON with exposed pad
The pad is electrically connected to the die substrate, typically tied to ground. The small footprint (6 mm x 8 mm) saves board space compared to SOIC-8 alternatives. The part is surface-mount only.