ST’s New 4Mbit EEPROMs Built to Support IoT Developments

November 22, 2019 by Lisa Boneta

The M95M04 devices support 4Mbit capacity and allow devices to capture and store more data using the serial interface peripheral (SPI) bus.

Many designers consider Electrically Erasable Programmable Read-Only Memory (EEPROM) a versatile asset for electronic design, especially in microcontrollers, because of its non-volatile memory, which allows for individual bytes to be erased and reprogrammed. While EEPROM was originally meant to store small amounts of data, Internet of Things (IoT) devices, require more storage.

STMicroelectronics recently introduced its new generation of memory chips that “combine unprecedented storage density with speed and reliability” to help improve the capabilities of everyday devices.


Block diagram of M95M04

Block diagram of STMicroelectronics first 4Mbit EEPROM chips. Image from STMicroelectronics


The M95M04 chips support 4Mbit capacity and allow devices to capture and store more data through the serial interface peripheral (SPI) bus. The M95M04 EEPROMs are available as compact, 8-bump wafer-level chip-scale packages (WLCSP), SO8N, and TSSOP8 packages. 

Benoit Rodrigues, division general manager of STMicroelectronics, explains that the M95M04 family is “the market’s first 4Mbit EEPROM devices ... produced in our own CMOS technology, which is now qualified at 110nm as the most advanced in the industry for EEPROMs.”


M95M04 Family to Enable Wireless and IoT Applications 

ST foresees that M95M04 will be useful in applications that require increased memory. This might entail increased data logging in smart meters and improved grid management. The device is also said to better log patients' data in medical devices and make way for new features in smart wearables. 


Extending Memory and Battery

In addition to increasing overall memory capacity, the new EEPROM is also designed to store memory on low power, which extends the longevity of battery runtime: specifically, it writes 512 bytes in 5ms to enable low latency of devices.


Bus master and memory devices on the SPI bus

Bus master and memory devices on the SPI bus. Image from STMicroelectronics

It supports a power supply range of 1.8V to 5.5V and has 40-year data retention, in contrast to many traditional EEPROMs that usually retain data for 10 years; thus, a 40-year retention period helps with the longevity of deployed products.


ST Prepares for More Wireless Solutions

The features of the new EEPROM chips warrant progress in many IoT applications and devices as they require increased memory, low latency, and low power consumption to optimize their real-time performance. 


Dimensions of M95M04-DR

Dimensions of M95M04-DR. Image from STMicroelectronics

We’ve previously looked at STMicroelectronics’ STM32 LoRaWAN software expansion package for firmware over-the-air updates, which is built to preserve the longevity of IoT devices in the field. The company's ST8500 PLC chipset for smart meter applications is another example of how ST seems mindful of burgeoning IoT applications.

With the addition of the 4-bit EEPROM chips, it seems that STMicroelectronics is continuing the effort to support self-sufficient and comprehensive wireless solutions.


Around the Industry

The new EEPROM chips act as a useful point of comparison to others like it in the industry.

For instance, Atmel’s family of EEPROM chips (AT25010B, AT25020B, AT25040B) are SPI compatible, offer max write cycles of 5ms, and data retention of 100 years. These chips offer  4,096 bits of serial EEPROM and 8-byte page write.

In July of this year, NXP announced the NXH5104—a 4Mbit serial EEPROM that offers WLCSP like the M95M04-DR, but falls short with a 256-byte page write, 10-year data retention, and limited support of voltage supply range. Another significant difference is that the NXH510 chips have 13 pins whereas the M95M04 chips have 8 pins.