Comparative Study of Various Latch-Type Sense Amplifiers

When the input voltage difference of a sense amplifier (SA) exceeds the offset voltage (VOS), the SA correctly detects it and outputs a large signal. However, when the input voltage is in a certain region, the SA can fail to sense the input voltage difference even if it is sufficiently large. This input voltage region is defined as the sensing dead zone of the SA. Because sensing dead zones differ depending on SAs and the input voltages to the SA differ depending on the memory devices, analyzing the sensing dead zone is very important. In this brief, we analyze the sensing dead zones of the most popular latch-type SAs: voltage- and current-latched SAs. Furthermore, a suitable latch-type SA scheme is suggested for various SA input voltages in terms of sensing delay, power consumption, and PDP, using a 65-nm predictive technology model at a VDD of 1.1 V.