Small serial EEPROM for configuration storage
The Microchip AT25020B-MAHL-E is a 2Kbit serial EEPROM with an SPI interface, organized as 256 x 8 bits. It clocks up to 20 MHz and runs on a supply from 1.8V to 5.5V, making it a drop-in for 3.3V or 5V logic systems. Write cycle time is 5ms per page or word, typical for this density class.
20 MHz SPI bus — timing margin for the system
At 20 MHz, the SPI clock period is 50 ns. That gives the host controller enough margin for moderate trace lengths on a 2-layer board, but keep the EEPROM close to the MCU if you are running at the full rate. The 5ms write cycle is a non-issue for configuration writes — it is the read speed that matters for boot-time parameter fetch.
Package and field-swap reality
This comes in an 8-UFDFN with an exposed pad (2x3 mm body). That is a small, low-profile package — great for space-constrained boards, but not something you swap with a soldering iron in the field. You need a hot-air station or reflow oven.
No last-time-buy notice, no EOL flag.