M34D64 M34D32 64/32 Kbit Serial I²C Bus EEPROM With Hardware Write Control on Top Quarter of Memory is electrically erasable programmable memory (EEPROM) manufactured by STMicroelectronics. It works with a voltage of 4.5V to 5.5V, supports I2C extended addressing, two-wire I2C serial interface, 400 kHz protocol. It has BYTE and PAGE WRITE (up to 32 Bytes), RANDOM and SEQUENTIAL READ modes, self-timed programming cycle, automatic address incrementing, enhanced ESD/Latch-Up behavior, more than 1 million erase/write cycles, more than 40 years data retention time.
The M34D64 and M34D32 are 64‑Kbit and 32‑Kbit serial I²C bus EEPROMs fabricated with STMicroelectronics’ high‑endurance CMOS technology. They operate with a two‑wire I²C interface supporting up to 400 kHz and are available in PDIP‑8, SO‑8 and other plastic packages.
A dedicated hardware Write Control (WC) pin protects the top quarter of the memory from inadvertent erase or write. When WC is high the upper quarter is write‑protected; when low normal write operations are allowed. The devices offer over one million erase/write cycles and a data retention of 40 years.
| Memory size | 64 Kbit (M34D64) / 32 Kbit (M34D32) |
|---|---|
| Interface | Two‑wire I²C serial, 400 kHz |
| Supply voltage (standard) | 4.5 V to 5.5 V |
| Supply voltage (‑W version) | 2.5 V to 5.5 V |
| Supply voltage (‑R version) | 1.8 V to 3.6 V |
| Endurance | > 1 Million erase/write cycles |
| Data retention | ≥ 40 years |
| Operating temperature | -40 °C to 125 °C |
| Storage temperature | -65 °C to 150 °C |
| Package types | PDIP‑8 and SO‑8 plastic packages |
| Write mode | Byte and Page write (up to 32 bytes) |
The devices are rated for more than one million erase/write cycles.
Data is retained for at least 40 years.
When WC is high it disables write operations to the top quarter of the memory; when low, normal writes are allowed.