DRAM and EMC

[ricky]

Hi,

I just want to ask that we have a highly critical EMC compliant system. We
need to make a choice between SRAM or DRAM in this. So, my question is,
which one of these is less sensitive to EMI (better suited for EMC critical
applications).

Thanks in advance.
ricky

 

[G Vandevalk]

Ricky:

Typically:

DRAM's are 1 Capacitor & 1 Access Transistor.
Leakage will cause the Capacitor to loose charge, and will need to be
refreshed after a set amount of time.

SRAM's are cross coupled transistors that retain the charge state through
feedback. Usually transistors.

Usually SRAM's are much more immune to EMI events than comparable technology
DRAM's
Note that both circuit types can be made more immune to EMI at the cost of
size or power.

YMMV
-- Gerry

 

[David R Brooks]

Traditionally, this was correct (SRAM better than DRAM).
Current designs are starting to change the balance, as SRAM cells keep
getting smaller & so less gate capacitance (read, less "hit" energy
required to flip the bit), while DRAM cells get all the capacitance
the process can give, to extend the refresh time.
A partial disturb is remedied at once in SRAM, byt the normal flipflop
regeneration. In DRAM, it must wait for the next refresh.


:Ricky:
:
:Typically:
:
RAM's are 1 Capacitor & 1 Access Transistor.
:Leakage will cause the Capacitor to loose charge, and will need to be
:refreshed after a set amount of time.
:
:SRAM's are cross coupled transistors that retain the charge state through
:feedback. Usually transistors.
:
:Usually SRAM's are much more immune to EMI events than comparable technology
RAM's
:Note that both circuit types can be made more immune to EMI at the cost of
:size or power.
:
:YMMV
:-- Gerry
:
:
::> Hi,
:>
:> I just want to ask that we have a highly critical EMC compliant system. We
:> need to make a choice between SRAM or DRAM in this. So, my question is,
:> which one of these is less sensitive to EMI (better suited for EMC
:critical
:> applications).
:>
:> Thanks in advance.
:> ricky
:>
:>
: