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FeRAM: Innovative alternative to EEPROM

FeRAM (Ferroelectric RAM)

FeRAM (ferroelectric RAM) is a type of non-volatile RAM (random access memory). The FeRAM is characterized by a particularly high data retention, i.e.: even at 125°C, the data is retained for over 10 years if the power supply is interrupted.

It is named after the ferroelectric dielectric of the capacitor. We will briefly discuss this at the end of the article in the context of how this storage technology works. First, however, we will take a look at the most important properties and some areas of application for the technology.

Table of contents

FeRAM Properties

FeRAM (Ferroelectric RAM) is a non-volatile memory that retains stored data even without power—unlike DRAM, which requires constant refresh cycles. FeRAM combines the speed of RAM with the persistence of Flash or EEPROM. It is pin-compatible with common EEPROMs, but offers significantly faster write performance, lower power consumption, and much higher write endurance.

Below, we summarize the key characteristics of FeRAM. Due to its comparatively higher cost, FeRAM is typically chosen only when at least one of these properties is essential for the application.

FeRAM consumes significantly less energy when writing and erasing data than other non-volatile memories like EEPROM or Flash. One reason is that FeRAM allows individual bits to be written directly—without the need to erase an entire memory block beforehand. Other technologies usually work block-wise and require energy-intensive charge pumps to perform write operations.

FeRAM operates at low voltages (typically 1.5–3.3 V) and can write data in just a few nanoseconds. This makes it ideal for power-sensitive applications, such as battery-operated devices or systems based on energy harvesting.

FeRAM supports extremely high write/erase cycles—up to 1014 per cell, according to some manufacturers. In contrast, EEPROM and Flash typically allow between 104 and 106 cycles. This makes FeRAM exceptionally durable and well suited for applications requiring frequent data writes, such as smart meters or industrial control systems with continuous data logging.

FeRAM is immune to magnetic fields and X-rays. Although the term “ferroelectric” may sound magnetic, FeRAM uses no magnetic materials. As a result, data is not affected by electromagnetic interference. In medical applications, this property is especially valuable—for example, in devices exposed to diagnostic environments or electromagnetic fields.

FeRAM memory cells are based on ferroelectric materials such as PZT (lead zirconate titanate), which can be electrically polarized in two stable states. These states represent logical “0” and “1” and persist even after power is removed. This enables fast, low-power, and non-volatile data storage. More on this can be found in the “How FeRAM Works” section.

FeRAM Applications

Please note: whether FeRAM is the right choice for a specific application depends on many design-specific factors. The following examples aim to provide context for FeRAM’s capabilities—not product recommendations.

FeRAM’s unique combination of power efficiency, write endurance, and robustness makes it suitable for various industrial and safety-critical applications. Here are some common use cases:

FeRAM is well suited for use in industrial control systems such as programmable logic controllers (PLCs). It reliably stores critical states, counters, or fault logs—even in the event of a sudden power loss. Its long write endurance eliminates the need for battery-backed RAM or frequent maintenance.

Smart meters and similar measurement systems benefit from FeRAM because they store small data sets frequently while operating on minimal power. With its fast write speed and long endurance, FeRAM supports reliable, long-term data logging—especially in devices that must function maintenance-free for years.

FeRAM is often chosen for systems that must retain the last known state during unexpected shutdowns—such as airbag modules in vehicles or flight recorders (“black boxes”) in aircraft. Its non-volatility and ultra-fast write performance ensure that no data is lost, even in the event of an immediate power failure.

Medical devices like insulin pumps or pacemakers use FeRAM to store critical patient data and configuration parameters. Its immunity to X-rays and ability to function in harsh environments make it highly reliable. Devices based on energy harvesting also benefit from FeRAM's low power requirements, as it allows storage with minimal available energy.

How FeRAM Works

Like DRAM, FeRAM cells consist of a transistor and a capacitor. However, the capacitor in FeRAM is built using a ferroelectric dielectric material (e.g., PZT), which allows it to store information via polarization—without suffering from leakage currents like conventional DRAM.

How is information stored in FeRAM?

When an electric field is applied, the polarization state of the ferroelectric material switches to represent a binary “0” or “1.” This state persists even after the power is removed. Reading the stored data involves briefly switching the polarization, which destroys the current value—hence FeRAM includes an automatic write-back (“destructive read”). Despite this, the process is extremely fast and highly energy-efficient.

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