NOVRAM - data storage without batteries

NOVRAM: data storage without batteries elektor december 1983 The CMOS RAM could be considered the forerunner of the true non-volatile memory. It is noted for its very low quiescent current consumption, so that the data in the mem- ory can be saved for months or even years with batteries providing the power. This is not a completely satisfactory solution, of course, but it is handy as far as it goes. In the last few years some proper non- volatile memories have appeared, notably the EAROM (Electrically Alterable ROM) and the EEPROM (Electrically Erasable PROM). These are ROMs whose contents can be altered electrically, without the device first having to be erased by exposure to UV light, for example. An extra pro- gramming voltage is often required, but in the newest types even that is unnecessary as a "high voltage" generator is integrated in the chip. A single voltage of 5 V is all that is needed. The biggest disadvantage of all these electri- cally rewritable ROMs is the long ti...