LE25U40 Serial Flash Memory onsemi LE25U40 4Mb Serial Flash Memory is an SPI bus device with a 512K x 8-bit configuration. It offers a high-performance Dual output and Dual I/O function while using a single 2.5V power supply. The LE25U40 also has a small sector erase capability, making it ideal for storing parameters or data that have fewer rewrite cycles. This device is housed in an 8-pin ultra-miniature package and is suited for applications such as portable devices.