Screening for Extended Temperature on SDRAM Memory

Temperature screening of commercial-grade memory is a proven cost effective way to produce extended temperature memory modules that are available with short production lead times.

The temperature range for screening is typically the industrial temperature E2 range from -40°C  (left) to +85°C (right):

Cold-Hot

Memory modules screened for industrial temperature are suitable for high reliability requirements such as rugged COTS computers, industrial computers, mobile PCs, embedded Single Board Computers (SBCs), telecommunication servers, networking appliances, military-aerospace systems, medical and science research instrumentation.

The screening of memory modules usually occurs at the time of manufacture. They are tested at both ends of the temperature range over a specified period of time while the test computer is operating a software diagnostic tool. This “active” burn-in, also called Test During Burn In (TDBI) will screen out potentially weak DRAM on the memory modules.

A “passive” burn-in approach on unpowered modules, is not used a screening technique because DRAM components must be powered on to frequently “refresh” the data. Beyond extended temperature screening, there are additional enhancements that provide further protection in environments with high moisture, humidity, shock, vibration or low flow air cooling:

  • Conformal Coating, Type 1B31 acrylic, MIL-I-46058 Rev. C. Type AR
  • Under-fill, epoxy-based
  • Thermal sensor, SPD defined for increase DRAM refresh rate or fan speed
  • Thermal heat spreader and/or aluminum heat sink