protecting dynamic RAM's

o 4 4 is 6 4 6 ill 4 E 6 Ilib a 4 * One of the most useful dynamic RAM"s, the 4116, unfortunately needs three supply voltages. Nothing can be done about this, even with the most sophist cated circuit. Although most data sheets imply that these supply voltages may be applied in an arbitrary true in all circum- sequence, this is not necessarily out here that even stances. We may cynically point though no sequence is specified, this does not necessarily imply that there is no need to account of the sequence! In practice it is happily not as bad as you might think: only when there is a question of overshoot on the supply lines causing the maximum supply voltages to be temporarily exceeded, is it important to ensure that the negative supply is present. The consequence of this is a considerable improvement of voltage regulation! ortant, aspect is the A second, probably more imp requirement that the negative supply voltage should never ever become positive. This can be arranged easily if...