256 Mbit NOR Flash in a 16-SOIC — what the FL-S series delivers
The Cypress S25FL256SDPMFV010 is a 256 Mbit SPI NOR Flash memory from the FL-S family, organized as 32M x 8 bits. It uses a Quad I/O SPI interface that clocks at up to 66 MHz, giving you a read throughput that's roughly 4x a standard SPI part without adding pins to the layout.
66 MHz Quad I/O — what the clock rate buys you
At 66 MHz in Quad I/O mode, the S25FL256SDPMFV010 can sustain around 33 MB/s read throughput on a good layout. That is enough to shadow-copy a firmware image into DRAM at boot without stalling the processor. If you are doing execute-in-place (XIP) from NOR, the 66 MHz ceiling means the flash is not the bottleneck for a 32-bit MCU running at 120 MHz or below — the bus turnaround and wait states will dominate. For designs that only need standard SPI at lower rates, the part still works; the quad mode is simply there when you need the extra margin.
Package and footprint — 16-SOIC with 7.50 mm width
The 1.27 mm pitch gives good routability on two-layer boards. No thermal pad to worry about — the NOR flash draws under 100 mA active current at 66 MHz, so the SOIC's copper leads handle the dissipation.