FRAM Memory Chips

FRAM memory chips have memory cells that contain a specific ferroelectric material such as a crystal of zirconium or titanium, or oxygen and lead. FRAM memory chips memory is much faster than Flash memory. Ferroelectric RAM (FeRAM) is a type of non-volatile memory based on electric field orientation and with near-unlimited number (exceeding 1010 for 5V devices and even more for 3.3V ones) of write-erase cycles. FRAM memory chips combines the advantages of SRAM in which writing is roughly as fast as reading (70-200 ns), and EPROM non-volatility and in-circuit programmability. Non-volatile FRAM memory offers an optimized, easy-to-use solution for a variety of advanced electronic metering systems, whether metering electricity, water, gas, or heat. FRAM memory chips do not yet offer the bit density of DRAM and SRAM, but they are non-volatile and faster than Flash/EEPROM memory (write times under 100 nanoseconds), and they have very low power requirements.

FRAM memory chips are an array of ferroelectric capacitors, a DRAM with the dielectric layer in the memory capacitors replaced with a thin ferroelectric film, typically made of lead zirconate titanate (PZT). The resulting FRAM memory chips are electrically similar to the capacitors used in a conventional DRAM chip, but the ferroelectric film will retain a electric field even after the charge in the capacitor drains. Depending on the direction of the current flow when the cell is charged, the film will be polarized into one of two directions. FRAM memory technology is compatible with industry standard CMOS manufacturing processes. A ferroelectric thin film is placed over CMOS base layers and sandwiched between two electrodes. Metal interconnect and passivation completes the process. It is possible to make a ferroelectric memory chip using two additional masking steps during normal semiconductor manufacture, leading to the possibility of full integration of FRAM into microcontrollers and other chips. Flash typically requires nine masks. This makes FRAM particularly attractive as an embedded non-volatile memory on microcontrollers, where the simpler process can reduce costs. However, FRAM memory semiconductors used to make FRAM memory chips are not commonly used elsewhere in integrated circuit manufacturing. FRAM memory chips are designed and manufactured to meet most industry specifications.

FRAM memory chips are used in many applications. Typically FRAM memory chips are found in electronics devices for storing small amounts of non-volatile data. Small FRAM memory chips with serial interfaces are commonly found in many electronics devices. A main vendor of FRAM memory chips is Ramtron International.

• A Guide to SPI FRAM Devices
  The SPI family of FRAM products offers the market serial high speed, low power, nonvolatile FRAM memory. SPI FRAM memory devices take advantage of FRAM's fast write performance that provides writing...
  (read more)
• Routines for 2-Wire FRAM Using Microchip MCUs
  This application note describes bulletproof random write- and read- block routines written specifically for the Ramtron FM24C04 and FM24C16 for Microchip microcontrollers (MCUs) where the processor is...
  (read more)
• Replacing SRAM with FRAM
  Ramtron offers three FRAM devices that are pin compatible with industry standard bytewide (x8) SRAMs. The FM1608 is an 8Kx8 and the FM1808 and FM18L08 are 32Kx8 devices, all of which may be used as...
  (read more)

Pages: 1 - 3 of 245