64 Mbit SPI DataFlash in a 5×6 mm UDFN
The Renesas AT45DB641E-MHN-T is a 64 Mbit serial DataFlash organized as 264 bytes per page across 32K pages, accessed over an SPI bus at up to 85 MHz.
SPI throughput and write timing for the BOM
At 85 MHz SPI clock in quad-I/O mode, the sustained read throughput is well above 40 MB/s — enough to shadow-copy code into RAM or stream boot data without stalling the core. The 8 µs page-write cycle and 5 ms page-erase cycle mean a full 264-byte page can be rewritten in under 6 ms, keeping firmware-over-the-air update windows short. The 64 Mbit density (8 MB) suits code storage for a Cortex-M class MCU or configuration data for an FPGA bitstream. The SPI interface keeps the pin count to six signals (CS, SCK, SI, SO, WP, HOLD) — no address lines, no parallel bus routing.
Active lifecycle and compliance posture
ROHS3 compliant (no exemptions), so it passes the substance-restriction audit for EU and UK markets without a waiver expiry date.