FERRO ELECTRIC RAM
INTRODUCTION
RAM IS A TYPE OF NON-VOLATILE READ/WRITE RANDOM ACCES SEMICONDUCTOR MEMORY.
FRAM COMBINES THE ADVANTAGES OF SRAM, EPROM AND DYNAMIC RAM.
IT IS FAST MEMORY WITH A VERY LOW POWER REQUIREMENT.
FRAM IS FOUND MAINLY IN SMALL CONSUMER DEVICES.
FRAM IS FASTER THAN FLASH MEMORY.
COMPONENTS OF FERRO ELECTRIC RAM
A FERROELECTRIC RAM CONSISTS OF A FERROELECTRIC CAPACITOR AND A MOS TRANSISTOR.
THE FRAM DIFFERS FROM DRAM IS ITS DIELECTRIC PROPERTIES OF CAPACITOR ELECTRODS .
FERROELECTRIC MATERIAL, DOES NOT NECESSARILY CONTAIN IRON.
THE WELL-KNOWN FERROELECTRIC SUBSTANCE IS BATIO3.
WORKING OF FRAM WRITING A BIT
ELECTRIC FIELD IS APPLIED TO FERROELECTRIC CRYSTAL
CENTRAL ATOM MOVES WITHIN IN THE CRYSTAL
THESE ATOMS PASSES THE ENERGY BARRIER
CAUSING A CHARGE SPIKE
INTERNAL CIRCUITS SENSE THE CHARGE SPIKE
SET THE MEMORY.
READING A BIT
DATA IS READ BY APPLYING AN ELECTRIC FIELD TO THE CAPACITOR.
THIS SWITCHES THE RAM INTO THE OPPOSITE STATE.
MORE CHARGE IS MOVED THAN IF THE CELL WAS NOT FLIPPED.
READING DESTROYS THE CONTENTS OF A CELL.WHICH MUST BE WRITTEN BACK AFTER READ.
SPECIFICATION
4MB FRAM NONVOLATILE MEMORY MODULE.
ORGANIZATION:4 BANKS >< 32K >< 32 BITS.
HIHEST DENSITY: FERROELECTRIC MEMORY OVER 22.4KB/MM.
10 YEAR DATA RETENSION AT 85O C.
UNLIMITED READ /WRITE CYCLES.
ADVANCED HIGH RELIABILITY FERROELECTRIC PROCESS