Extra Margin Adjustment (EMA) for ARM’s Artisan 90nm SRAM, что это такое? Опции

[yes]

Вот есть такое описание (ниже),
+ табличка, где перечислено
EMA Result
000 Default, normal operation
001 Adds 10% additional delay
010 Adds 20% additional delay
011 Maximum delay, tolerates about 30% variation in read current

причем в синопсиских либах на эту память времянка так и зависит от этого ЕМА
000 - самая быстрая 001 - на 10% похуже и т.д.

ничего не нагуглил и в документах по этой памяти ничего больше нет

вопросы - влияет ли это ЕМА на физические характеристики (типа ток чтения/записи)?
или это какой-то параметр BISTа, задающий разные критерии выбраковки цела?
и вообще если я хочу получить более быструю память должен я его увеличивать или уменьшать?


ARM’s Artisan 90nm SRAM, register file, andROMgenerators haveEMAcapability. To achieve
correct timing, you have to consider signal integrity effects such as crosstalk, IR drop, and glitches
(e.g. [10]). You also have to consider built-in self-repair (BISR) with respect to marginal timing
issues. For instance, if a memory is tested at start-up, its temperature will be lower than later during
operation (e.g. 25C versus 100C). Timing defects can be present without being active at the
initially lower temperature. Table 2 describes the EMA values in detail.
For example, a BISR algorithm runs in “000” mode at startup, presumably at room temperature,
and reconfigures/repairs the memory based on these results. The algorithm could then set EMA to
001, providing a 10% guard band to protect against any problems resulting from higher
temperature operation after the device warms up. Similarly, a low frequency design might be
tested at room temperature, but it has to operate at a reduced margin to ensure against signal
integrity issues. Since EMA does not increase the area of the memory, the decision to use it or not
depends only on performance needs and overall design robustness.
Typically, a one-digit change in binary value results in a 10% change in time.