SST39VF400A-70-4I-EKE

SST39VF400A-70-4I-EKE is a 4‑Mbit NOR flash memory from SST designed as parallel (8‑bit) code storage for embedded systems. It typically operates from a 5V supply and provides a fast 70 ns read access time. The device is organized as 512K × 8 (4,194,304 bits total) and uses the standard NOR flash command set for Read, Program (byte/word), Sector/Block Erase, Chip Erase, and status/lock operations. It supports hardware protection features (e.g., block/region protection and status polling) to guard firmware against unintended writes. The suffixes indicate speed (70), package/variant (4I), and RoHS-compliant packaging (EKE). Applications include firmware storage for microcontrollers, boot ROMs, and other code-storage roles in embedded systems, often used in memory-mapped or standalone flash configurations. For exact electrical specs, block/sector sizes, programming sequences, and timing diagrams, refer to the official SST datasheet for this exact variant.

Equivalent parts (4Mbit, 8‑bit parallel NOR, 5V, ~70ns):
- Macronix MX29F400AB/AX
- ST M29W040
- Spansion S29GL040
- Atmel AT49F040
- Winbond W29C040
Note: pinout, voltage, and command sets differ; verify datasheets and timing before substitution.

Key features of SST39VF400A-70-4I-EKE:
- 4 Mbit (512 KB) non-volatile flash memory
- 8-bit data bus; 5V single-supply operation
- 70 ns random access time
- Industrial temperature range: -40°C to +85°C
- Supports page programming and sector/block erase (plus chip erase)
- Endurance: up to ~100,000 program/erase cycles
- Data retention: >20 years (typical)
- Ready/Busy status with protection features (lock regions)
- Low-power standby and automatic power-down
- Standard SST flash command set for unlock, program, and erase operations
Note: exact block sizes and page sizes are device-family dependent; refer to datasheet for precise block/sector layout.

- Pin count: 32 pins (32‑pin package; A0–A18, DQ0–DQ7, /CS, /OE, /WE, Vcc, Vss).
- Function: 4‑Mbit asynchronous NOR flash memory with a parallel (8‑bit) data bus and 70 ns access time; supports read, program (write), and erase. Address lines A0–A18; control lines /CS, /OE, /WE. Used for nonvolatile storage of code/data.

Manufacturer: Silicon Storage Technology (SST).
What kind of company: SST is a semiconductor company that designs and manufactures non-volatile flash memory products (NOR/NAND flash) used in embedded and other memory applications.

Nonvolatile code and data storage for embedded systems. Key applications include firmware/BIOS storage for microcontroller/MPU-based devices, automotive ECUs and infotainment, industrial controllers, telecom equipment, and consumer electronics (set-top boxes, digital cameras, handheld devices). Also suitable for data logging and configuration storage in instrumentation and portable equipment. The device’s 4 Mbit capacity and 70 ns access time support high-speed boot code, executable firmware, and parameter storage in space-constrained designs.

32-pin SOP (SO-32) plastic package.