GENERAL DESCRIPTION
   The W25B40 / W25B40A is a 4Mb (512KB) Serial Flash Memory with erasable sectors that allows for boot code and parameter storage. The W25B40 / W25B40A is packaged in an 8-pin SOIC 150-mil and is compatible with the standard W25P40 specification with the following exceptions.

FEATURES
• W25B40 / W25B40A 4M-bit Serial Flash
   – 4M-bit /512K-byte (524,288)
   – 256-bytes per programmable page
• Compatible with W25P40 with special
   features
   – Small Boot and Parameter Sectors
   – Write protection of Boot/Parameter area
• Variable Sector Sizes for Boot Code and
   Parameter Storage
   – Seven sectors of 64KB
   – One sector each of 32KB, 16Kb and 8KB
   – Two sectors of 4KB
   – Bottom Boot organization (standard)
   – Top Boot organization (special order)
• 4-pin SPI Serial Interface
   – Clock, Chip Select, Data In, Data Out
   – Easily interfaces to popular microcontrollers
   – Compatible with SPI Modes 0 and 3
   – Optional Hold function for SPI flexibility
• Low Power Consumption, Wide
   Temperature Range
   – Single 2.7 to 3.6V supply
   – 5mA active current, <1µA Power-down
   – -40° to +85°C operating range
• Fast and Flexible Serial Data Access
   – Clock operation to 40MHz
   – Byte-addressable Read and Program
   – Auto-increment Read capability
   – Manufacturer and Device ID
• Programming Features
   – Page program up to 256 bytes 2mS
   – Sector Erase 120mS to 650mS
   – Chip erase 5.5 seconds
   – 100,000 erase/write cycles
   – Twenty-year data retention
• Software and Hardware Write
   Protection
   – Write-Protect all or portion of memory
   – Enable/Disable protection with /WP pin
• SOIC Compatible Packaging
   – Tiny 8-pin SOIC 150mil
• Ideal for systems with limited pins,
   space, and power
   – Controller-based serial code-download
   – µC systems storing data, text or voice
   – Battery-operated and portable product