X24640

The X24640 is a CMOS Serial E2PROM, internally organized 8K x 8. The device features a serial interface and software protocol allowing operation on a simple two wire bus.

The bus of X24640 operates at 400 KHz all the way down to 1.8V. Three device select inputs (S0S2) allow up to eight devices to share a common two wire bus.

A Write Protect Register at the highest address location, FFFFh, provides three write protection features: Software Write Protect, Block Lock Protect, and Programmable Hardware Write Protect. The Software Write Protect feature prevents any nonvolatile writes to the device until the WEL bit in the Write Protect Register is set. The Block Lock Protection feature gives the user four array block protect options, set by programming two bits in the Write Protect Register. The Programmable Hardware Write Protect feature allows the user to install the X24640 with WP tied to VCC, program and Block Lock the desired portions of the memory array in circuit, and then enable the In Circuit Programmable ROM Mode by programming the WPEN bit in the Write Protect Register. After this, the Block Locked portions of the array, including the Write Protect Register itself, are permanently protected from being erased.