Apple Certification Exam 9L0-509
Filed Under (Adobe) by admin on 02-09-2008
To write to memory, the row is opened and a given column’s sense amplifier is temporarily forced to the desired state 9L0-402 and drives the bit line which charges the capacitor to the desired value. The amplifier will then drive the bit lines to the desired state and hold it stable even after the forcing is removed. During a write to a particular cell, the entire row is read out, one value changed, and then the entire row is written back in, as illustrated in the figure to the right.
# The sense amplifier Apple 9L0-402 is switched on. The positive feedback takes over and amplifies the small voltage difference until one bit line is fully low and the other is fully high. At this point, the column can be read.
# At the end of a read cycle, the row values must be restored to the capacitors, which were depleted during the read: the bit line of the storage cell is also driven to full voltage (refreshed) by the action of the 9L0-509 sense amplifier. Due to the length of the bit line, this takes significant time beyond the end of sense amplification.
There are many numbers 9L0-509 dumps required to describe the speed of DRAM operation. Here are some examples for two speed grades of asynchronous DRAM, from a data sheet published in 1998

