Fujitsu has launched a new 4Mbit Serial FeRAM with upper compatibility to EEPROM

Optimal non-volatile memory for real-time data logging such as 3D positioning data of event data recorder


Fujitsu Semiconductor Limited announced that it has developed the MB85RS4MT, a 4Mbit FeRAM that has the highest density in Fujitsu's serial interface family of FeRAM non-volatile memories. Mass-produced products are currently available.

In a changing environment, with increasing volume of sensor information data and expanding edge-computing, there are a number of requests from the customers that they prefer increased read/write cycles, shortened data writing times, and increased memory density. This new product is a solution to meet the requirements of customers who are not satisfied with existing EEPROMs.

The MB85RS4MT is optimal for various applications requiring real-time or frequent data logging such as driving/navigation recorders, industrial robots, computer numerical control(CNC) machine tools, measurement equipment, smart meters, and consumer equipment.

MB85RS4MT PackageMB85RS4MT Package
Fig.1:Read/Write Cycles ComparisonFig.1:Read/Write Cycles Comparison
Fig.2:Write Time Comparison(at voltage drop)Fig.2:Write Time Comparison(at voltage drop)


Fujitsu Semiconductor launches a new 4Mbit FeRAM product, the MB85RS4MT, that has the highest density in our FeRAM lineup of serial peripheral interface (SPI) products. For around 20 years, Fujitsu Semiconductor has mass-produced FeRAM non-volatile memory products featuring high read/write endurance, high-speed write operation, and low power consumption.

This FeRAM product features a guaranteed 10 trillion read/write cycles, which is about 10 million times of that competitive non-volatile memory, EEPROM.
Therefore, the guaranteed read/write cycle limit does not become a bottleneck in customer product design, even if the MB85RS4MT is used for memory for frequent data logging of sensor information in edge-computing. (Fig.1)

The FeRAM product also features high-speed write operation by writing data with an overwrite sequence with no erase operation. While conventional non-volatile memories like EEPROM and flash memory require additional time for the erase operation in addition to normal write operation.
This fast write operation helps to protect data against sudden voltage drops such as power outages during writing. (Fig.2)

Since the MB85RS4MT operates within a wide power supply voltage range, from 1.8V to 3.6V, it can be used in customer end-products with other peripheral electronics components operating at either 1.8V or 3.6V. Its operating currents are very small, with a maximum operating current of 250μA at 1MHz operation and a maximum standby current of 50μA. This means, this FeRAM product has the advantage of low power consumption, due to its low operating voltage and low operating current.

The FeRAM product is in an industry-standard 8-pin SOP package, making it easy to replace existing EEPROM in 8-pin SOP. This enables customers to switch to FeRAM products without requiring major design changes to motherboards in end-products.

Fujitsu Semiconductor announced new FeRAM products operating at −55°C in April and new 8Mbit parallel FeRAM products in June. This time it has developed new 4Mbit serial FeRAM products with SPI interface. Fujitsu continues to develop memory products that are optimized for various applications in order to solve customer problems.

Key Specifications

Part NumberMB85RS4MT
Density(configuration)4Mbit (512K x 8bit)
InterfaceSPI (Serial Peripheral Interface)
Operating frequencyMaximum 40MHz
Operating voltage1.8V to 3.6V
Operating temperature range-40°C to +85°C
Read/Write endurance10 trillion times (1013 times)
Package8-pin SOP


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