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Reasons to Choose ReRAM

Introducing ReRAM

RAMXEED offers two types of non-volatile memory: FeRAM and ReRAM. Since the two types have different characteristics, they are specialized toward different applications. The main advantage of ReRAM is that the operating current during read operations is very small. Since the number of data read operations is unlimited, ReRAM is suitable for applications with high program read frequency.
Since the current during read operations is very small, it can also be expected to extend the battery life of small battery-powered devices. For example, it is ideal for small wearable devices such as hearing aids and smartwatches. On the other hand, the advantage of FeRAM is that it guarantees a large number of data rewrites. Because it allows data to be rewritten up to 100 trillion times, FeRAM is suitable for applications where data is continuously written in real time. For example, it is used as memory to record information in meters, industrial robots, and automobiles.

Features of ReRAM and FeRAM

ReRAM FeRAM
Non-volatile
  • Retains data even when power is turned off
Non-volatile
  • Retains data even when power is turned off
Low read current
  • Average: 0.15mA (at 5MHz)
  • Maximum: 0.7mA (at 10MHz)
High read/write cycle endurance
  • Guaranteed up to 100 trillion rewrites
Large capacity
  • Maximum: 12Mbit
Fast write speed
  • Enables overwriting of data (erase operations are not required)
Ultra-compact package
  • 2mm×3mm (12Mbit version)
Low power consumption
  • Power saving due to short write time
  • No internal boost is required for writing
FeRAM
Non-volatile
  • Retains data even when power is turned off
High read/write cycle endurance
  • Guaranteed up to 100 trillion rewrites
Fast write speed
  • Enables overwriting of data (erase operations are not required)
Low power consumption
  • Power saving due to short write time
  • No internal boost is required for writing

Positioning of non-volatile memory types

Positioning of non-volatile memory types Positioning of non-volatile memory types

1.Features of ReRAM

ReRAM has four key features: non-volatility, low read current, high capacity, and ultra-compact package.

Non-volatile
  • Retains data even when power is turned off
  • - Battery-free (enables greener products)
Low read current
  • Very low average 0.15mA (at 5MHz)
  • 0.7mA even at maximum (at 10MHz)
Large capacity
  • 12Mbit memory density
Ultra-compact package
  • 2mm×3mm (11-pin WL-CSP)

The table below shows a comparison of features with existing memory products. The three general-purpose memories listed here—EEPROM, flash memory, and SRAM—are all types of memory that can be easily replaced with ReRAM. The table shows that ReRAM has a low read and write current compared to other types of memory. The operating power supply voltage is also from as low as 1.6V, enabling low power consumption during operation. In addition, compared with SRAM, which requires a battery to retain data when the power is turned off, ReRAM—which is non-volatile memory—does not require a battery, making it an easy-to-use memory type. For these reasons, since ReRAM can be said to have low power consumption during operation, we can also say that it is advantageous memory type in terms of low power consumption.

Comparison of features with general-purpose memory

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Item ReRAM EEPROM Flash memory SRAM
Memory type Non-volatile Non-volatile Non-volatile Volatile
Data retention battery Not required Not required Not required Not required
Read current 0.15mA
(@5MHz)
0.15mA
(@5MHz)
4mA
(@33MHz)
20mA
(@55ns)
Write current 1.5mA 3mA 15mA 20mA
(@55ns)
Read cycles Unlimited Unlimited Unlimited Unlimited
Write cycles 1 million times 1 million times 100,000 times. Unlimited
Power supply voltage (minimum) 1.6V〜 1.8V〜 2.7V〜 2.7V〜

High capacity and compact package

The package of our ReRAM products is a WL-CSP (Wafer Level Chip Size Package) with dimensions of 2mm x 3mm (6mm²). While the 8-pin SOPs found in many non-volatile memory SPI interfaces have legs (leads) extruding from the package, the WL-CSP has contact balls on the backside, reducing its mounting area footprint. For example, when compared to 4Mbit 8-pin SOP memory, the 12Mbit ReRAM has triple the memory density with over an 80% reduction in footprint size.

SOP and WL-CSP mounting area comparison

SOP and WL-CSP mounting area comparison

ReRAM pin layout and dimensions
(8Mbit and 12Mbit products are the same)

ReRAM pin layout and dimensions

Low read current

The average ReRAM read current is 0.15mA at 5MHz. This is around 95% lower than the average EEPROM read current of 3.0mA at the same 5MHz operating frequency. This feature makes it ideal for wearable devices that run on batteries. Specifically, in hearing aids, initial setup (parameter) data is recorded, and the data is then frequently accessed and used (by data read operation) when the device is in use. In such applications, a low read current can reduce battery consumption. Among battery-powered electrical products, it can be said that our ReRAM is particularly suitable for applications in wearable devices which require a small memory package size and where data is read frequently.

Read current comparison

Read current comparison

2.Customer issues and solutions with ReRAM

If you have any of the following issues, you may be able to solve them by replacing existing memory with our ReRAM memory.

Issue

We are currently using EEPROM, but there is no high-capacity lineup. Replacement with flash memory is difficult because it would require a software update.

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Solutions with ReRAM

Our ReRAM products have capacity of up to 12Mbit. It is easy to replace EEPROM with ReRAM, since there is no need for erase operations or sector-by-sector writing.

Issue

We want to increase memory density, but the package size cannot be increased because the available mounting space is limited.

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Solutions with ReRAM

We can supply 8Mbit and 12Mbit products in a small package with dimensions of 2mm x 3mm. Even if you are using 8Mbit ReRAM, you can replace it with 12Mbit ReRAM with the same pin layout and package size.

Issue

We want to reduce power consumption, but it is difficult to significantly reduce it with conventional non-volatile memory.

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Solutions with ReRAM

The read current of ReRAM is less than 10% that of other non-volatile memory such as EEPROM, and the power supply voltage is 1.6V, enabling a reduction in power consumption.

Issue

Since our product has a small battery, not only average current consumption but also peak current is a concern.

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Solutions with ReRAM

ReRAM also has low peak current, making it suitable for use with small batteries.