FRAM is one of the latest memories seen in some of the micro controllers and is also used as external memory in designs. Let us get into high level details of this memory type.
These days we hear about FRAM memory inside the microcontroller or the FRAM usage external to microcontrollers. So, the doubts are like is it a volatile or non-volatile memory? How is it going to change our present design methodologies? How does it compare against existing memories? Let us learn few points to refresh our knowledge.
FRAM is actually a Random Access Memory but on-volatile. Ferroelectric layer used helps to achieve the non-volatility. When we say, non-volatile, this can be regarded as flash memory. FRAM construction is similar to DRAM, when we say this, there is a capacitor and it's associated control circuitry to read and write data. One of the main problem with DRAM is that data is to refreshed at regular intervals and it need to be powered continuously. FRAM and DRAM differ only during the Read cycle. The write cycle procedure is the same for both. FRAM is bit-addressable as the structure is similar to DRAM. The Ferroelectric materials used has two states based on the atom orientation inside the crystalline structure. This atom state is what determines '1' or '0'.
To summarize in one sentence, FRAM combines the fast read and write nature of DRAM and non-volatile nature of Flash.
Advantages of F-RAM compared to Flash Memory:
1. Higher Data Retention
2. Low Power consumption than EEPROM and Flash
3. Fast Write performance -- around 150-200ns, flash requires time in milliseconds to write
4. More number of Read and Write Cycles (Endurance)
5. Robust - Data retention for a good period of time even at high temperatures
6. The cost required during fabrication to embed FRAM into controllers like MCU is lesser than Flash Memory
7. Can operate at voltages as low as 1.5V
8. FRAMs have resistance to Gamma radiation
Disadvantages of FRAM:
1. Costly than flash. This is why FRAMS are used in applications, with low memory requirements.
2. Storage Density is less --- The ferroelectric materials property degrades as size goes beyond a specific limit
3. FRAMs can store a bit per cell where as flash memory can store multiple bits per cell
4. Read cycle takes little longer
F-RAM Applications
External/Internal non-volatile memory to microcontroller
Replacement for EEPROM
What is the type of FRAM material used?
Lead Zirconate Titanate (PZT)
What are alternatives to FRAM?
MRAM - Magnetoresistive random-access memory
Chips available in the market
CY15B104Q-SXI ---- SPI based FRAM from Cypress Semi-conductor
MSP430FR21xx ---- Microcontroller has 3.75KB of internal FRAM (Program Memory)
These days we hear about FRAM memory inside the microcontroller or the FRAM usage external to microcontrollers. So, the doubts are like is it a volatile or non-volatile memory? How is it going to change our present design methodologies? How does it compare against existing memories? Let us learn few points to refresh our knowledge.
FRAM is actually a Random Access Memory but on-volatile. Ferroelectric layer used helps to achieve the non-volatility. When we say, non-volatile, this can be regarded as flash memory. FRAM construction is similar to DRAM, when we say this, there is a capacitor and it's associated control circuitry to read and write data. One of the main problem with DRAM is that data is to refreshed at regular intervals and it need to be powered continuously. FRAM and DRAM differ only during the Read cycle. The write cycle procedure is the same for both. FRAM is bit-addressable as the structure is similar to DRAM. The Ferroelectric materials used has two states based on the atom orientation inside the crystalline structure. This atom state is what determines '1' or '0'.
To summarize in one sentence, FRAM combines the fast read and write nature of DRAM and non-volatile nature of Flash.
Advantages of F-RAM compared to Flash Memory:
1. Higher Data Retention
2. Low Power consumption than EEPROM and Flash
3. Fast Write performance -- around 150-200ns, flash requires time in milliseconds to write
4. More number of Read and Write Cycles (Endurance)
5. Robust - Data retention for a good period of time even at high temperatures
6. The cost required during fabrication to embed FRAM into controllers like MCU is lesser than Flash Memory
7. Can operate at voltages as low as 1.5V
8. FRAMs have resistance to Gamma radiation
Disadvantages of FRAM:
1. Costly than flash. This is why FRAMS are used in applications, with low memory requirements.
2. Storage Density is less --- The ferroelectric materials property degrades as size goes beyond a specific limit
3. FRAMs can store a bit per cell where as flash memory can store multiple bits per cell
4. Read cycle takes little longer
F-RAM Applications
External/Internal non-volatile memory to microcontroller
Replacement for EEPROM
What is the type of FRAM material used?
Lead Zirconate Titanate (PZT)
What are alternatives to FRAM?
MRAM - Magnetoresistive random-access memory
Chips available in the market
CY15B104Q-SXI ---- SPI based FRAM from Cypress Semi-conductor
MSP430FR21xx ---- Microcontroller has 3.75KB of internal FRAM (Program Memory)
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